I am developing third party IME in metro application (C#) ,I need to understand that how to text service interact to Text Service Framework (TSF).
The Text Services Framework is available from a C++ component in a Metro style app. Here is a list of the available COM APIs from C++ in a Metro style app. Scroll down to Text Services Framework and you will see that most APIs are available.
In terms of how to do it, it depends on what you want to do -- you call COM components in the normal way that you would from any other C++ app. Here is a reference that should help on various usages to TSF APIs.