diff --git a/core/README.md b/core/README.md
index 2b437ac4..a3603068 100644
--- a/core/README.md
+++ b/core/README.md
@@ -2,70 +2,6 @@ Introduction
 ==============
 This project aims to demonstrate wasm app management and programming model of WAMR.
 
-Directory structure
-------------------------------
-<pre>
-simple/
-├── build.sh
-├── CMakeLists.txt
-├── README.md
-├── src
-│   ├── ext-lib-export.c
-│   ├── iwasm_main.c
-│   └── main.c
-└── wasm-apps
-    ├── event_publisher
-    │   └── event_publisher.c
-    ├── event_subscriber
-    │   └── event_subscriber.c
-    ├── request_handler
-    │   └── request_handler.c
-    ├── request_sender
-    │   └── request_sender.c
-    ├── sensor
-    │   └── sensor.c
-    └── timer
-        └── timer.c
-</pre>
-
-- build.sh
-  The script to build all binaries.
-- CMakeLists.txt
-  CMake file used to build the simple application.
-- README.md
-  The file you are reading currently.
-- src/ext-lib-export.c
-  This file is used to export native APIs. See README.md in WAMR root directory for detail.
-- src/iwam_main.c
-  This file should be implemented by platform integrator in which a host interface is provided to interact with WAMR app-manager. See `{WAMR_ROOT}/core/app-mgr/app-mgr-shared/app-manager-export.h` for the definition of the host interface.
-```
-  /* Interfaces of host communication */
-typedef struct host_interface {
-    host_init_func init;
-    host_send_fun send;
-    host_destroy_fun destroy;
-} host_interface;
-```
-```
-host_interface interface = {
-                             .init = host_init,
-                             .send = host_send,
-                             .destroy = host_destroy
-                           };
-```
-This interface is passed to app-manager by calling
-```
-app_manager_startup(&interface);
-```
-
-The `host_init_func` is automatically called when app-manager startup. And `host_send_fun` will be called by app-manager to send data to host anytime.
->Note: Currently since app-manager will keep running and never exit, `host_destroy_fun` has no chance to get executed. So you can leave this API implementation empty.
-
-- src/main.c
-  The main file.
-- wasm-apps
-  Source files of sample wasm applications.
-
 Build all binaries
 ==============
 Execute the build.sh script then all binaries including wasm application files would be generated in 'out' directory.