how to pass parent process data to subprocess in process model

First, In the subprocess add a process variable and check the Parameter (Allow the value for the variable to be provided when starting a process) checkbox.

Then, in the main process, go to the the setup tab of sub process smart service, and in the input variable section you will see the sub process pv (if you don't refresh). Select the main process pv you want to pass to that. Also Check "Pass as reference". 

If you want the value to be returned back to the main PM add Output Variable too (Just below it)

Thanks for your answer I got it