diff --git a/trunk/src/app/srs_app_config.cpp b/trunk/src/app/srs_app_config.cpp
index 27c398ea16..9f5e74504f 100644
--- a/trunk/src/app/srs_app_config.cpp
+++ b/trunk/src/app/srs_app_config.cpp
@@ -46,6 +46,7 @@ using namespace std;
 #include <srs_kernel_file.hpp>
 #include <srs_app_utility.hpp>
 #include <srs_core_performance.hpp>
+#include <srs_kernel_file.hpp>
 
 using namespace _srs_internal;
 
@@ -240,6 +241,97 @@ int SrsConfDirective::parse(SrsConfigBuffer* buffer)
     return parse_conf(buffer, parse_file);
 }
 
+int SrsConfDirective::persistence(SrsFileWriter* writer, int level)
+{
+    int ret = ERROR_SUCCESS;
+    
+    static char SPACE = SRS_CONSTS_SP;
+    static char SEMICOLON = SRS_CONSTS_SE;
+    static char LF = SRS_CONSTS_LF;
+    static char LB = SRS_CONSTS_LB;
+    static char RB = SRS_CONSTS_RB;
+    static const char* INDENT = "    ";
+    
+    // for level0 directive, only contains sub directives.
+    if (level > 0) {
+        // indent by (level - 1) * 4 space.
+        for (int i = 0; i < level - 1; i++) {
+            if ((ret = writer->write((char*)INDENT, 4, NULL)) != ERROR_SUCCESS) {
+                return ret;
+            }
+        }
+        
+        // directive name.
+        if ((ret = writer->write((char*)name.c_str(), (int)name.length(), NULL)) != ERROR_SUCCESS) {
+            return ret;
+        }
+        if (!args.empty() && (ret = writer->write((char*)&SPACE, 1, NULL)) != ERROR_SUCCESS) {
+            return ret;
+        }
+        
+        // directive args.
+        for (int i = 0; i < (int)args.size(); i++) {
+            std::string& arg = args.at(i);
+            if ((ret = writer->write((char*)arg.c_str(), (int)arg.length(), NULL)) != ERROR_SUCCESS) {
+                return ret;
+            }
+            if (i < (int)args.size() - 1 && (ret = writer->write((char*)&SPACE, 1, NULL)) != ERROR_SUCCESS) {
+                return ret;
+            }
+        }
+        
+        // native directive, without sub directives.
+        if (directives.empty()) {
+            if ((ret = writer->write((char*)&SEMICOLON, 1, NULL)) != ERROR_SUCCESS) {
+                return ret;
+            }
+        }
+    }
+    
+    // persistence all sub directives.
+    if (level > 0) {
+        if (!directives.empty()) {
+            if ((ret = writer->write((char*)&SPACE, 1, NULL)) != ERROR_SUCCESS) {
+                return ret;
+            }
+            if ((ret = writer->write((char*)&LB, 1, NULL)) != ERROR_SUCCESS) {
+                return ret;
+            }
+        }
+        
+        if ((ret = writer->write((char*)&LF, 1, NULL)) != ERROR_SUCCESS) {
+            return ret;
+        }
+    }
+    
+    for (int i = 0; i < (int)directives.size(); i++) {
+        SrsConfDirective* dir = directives.at(i);
+        if ((ret = dir->persistence(writer, level + 1)) != ERROR_SUCCESS) {
+            return ret;
+        }
+    }
+    
+    if (level > 0 && !directives.empty()) {
+        // indent by (level - 1) * 4 space.
+        for (int i = 0; i < level - 1; i++) {
+            if ((ret = writer->write((char*)INDENT, 4, NULL)) != ERROR_SUCCESS) {
+                return ret;
+            }
+        }
+        
+        if ((ret = writer->write((char*)&RB, 1, NULL)) != ERROR_SUCCESS) {
+            return ret;
+        }
+        
+        if ((ret = writer->write((char*)&LF, 1, NULL)) != ERROR_SUCCESS) {
+            return ret;
+        }
+    }
+    
+    
+    return ret;
+}
+
 // see: ngx_conf_parse
 int SrsConfDirective::parse_conf(SrsConfigBuffer* buffer, SrsDirectiveType type)
 {
@@ -1424,7 +1516,31 @@ int SrsConfig::parse_options(int argc, char** argv)
 int SrsConfig::persistence()
 {
     int ret = ERROR_SUCCESS;
-    // TODO: FIXME: implements it.
+    
+    // write to a tmp file, then mv to the config.
+    std::string path = config_file + ".tmp";
+    
+    // open the tmp file for persistence
+    SrsFileWriter fw;
+    if ((ret = fw.open(path)) != ERROR_SUCCESS) {
+        return ret;
+    }
+    
+    // persistence root directive to writer.
+    if ((ret = root->persistence(&fw, 0)) != ERROR_SUCCESS) {
+        ::unlink(path.c_str());
+        return ret;
+    }
+    
+    // rename the config file.
+    if (::rename(path.c_str(), config_file.c_str()) < 0) {
+        ::unlink(path.c_str());
+        
+        ret = ERROR_SYSTEM_CONFIG_PERSISTENCE;
+        srs_error("rename config from %s to %s failed. ret=%d", path.c_str(), config_file.c_str(), ret);
+        return ret;
+    }
+    
     return ret;
 }
 
diff --git a/trunk/src/app/srs_app_config.hpp b/trunk/src/app/srs_app_config.hpp
index 7479c3f248..650033a27c 100644
--- a/trunk/src/app/srs_app_config.hpp
+++ b/trunk/src/app/srs_app_config.hpp
@@ -34,6 +34,8 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include <srs_app_reload.hpp>
 
+class SrsFileWriter;
+
 namespace _srs_internal
 {
     class SrsConfigBuffer;
@@ -136,6 +138,11 @@ class SrsConfDirective
     * parse config directive from file buffer.
     */
     virtual int parse(_srs_internal::SrsConfigBuffer* buffer);
+    /**
+     * persistence the directive to writer.
+     * @param level, the root is level0, all its directives are level1, and so on.
+     */
+    virtual int persistence(SrsFileWriter* writer, int level);
 // private parse.
 private:
     /**
diff --git a/trunk/src/kernel/srs_kernel_consts.hpp b/trunk/src/kernel/srs_kernel_consts.hpp
index 94d8ef0a3c..8b3b9bdcfb 100644
--- a/trunk/src/kernel/srs_kernel_consts.hpp
+++ b/trunk/src/kernel/srs_kernel_consts.hpp
@@ -194,6 +194,14 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define SRS_CONSTS_CR '\r' // 0x0D
 // LF             = <US-ASCII LF, linefeed (10)>
 #define SRS_CONSTS_LF '\n' // 0x0A
+// SP             = <US-ASCII SP, space>
+#define SRS_CONSTS_SP ' ' // 0x20
+// SE             = <US-ASCII SE, semicolon>
+#define SRS_CONSTS_SE ';' // 0x3b
+// LB             = <US-ASCII SE, left-brace>
+#define SRS_CONSTS_LB '{' // 0x7b
+// RB             = <US-ASCII SE, right-brace>
+#define SRS_CONSTS_RB '}' // 0x7d
 
 ///////////////////////////////////////////////////////////
 // HTTP consts values
diff --git a/trunk/src/kernel/srs_kernel_error.hpp b/trunk/src/kernel/srs_kernel_error.hpp
index bb7fddcefb..f9df9d3924 100755
--- a/trunk/src/kernel/srs_kernel_error.hpp
+++ b/trunk/src/kernel/srs_kernel_error.hpp
@@ -97,6 +97,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define ERROR_SYSTEM_DIR_EXISTS             1056
 #define ERROR_SYSTEM_CREATE_DIR             1057
 #define ERROR_SYSTEM_KILL                   1058
+#define ERROR_SYSTEM_CONFIG_PERSISTENCE     1059
 
 ///////////////////////////////////////////////////////
 // RTMP protocol error.