Why mask not aligning anymore? Help me please.

Hi Jerry,

Sorry. Are you saying the source footage is at a different frame rate than the sequence? That should not matter. I tried it myself and had no trouble. That said, it is always a good idea if your source footage matches your sequence settings if at all possible. Handling files in any way, like rendering and playback, works better with matching settings.

Back to masking, controls are found in the Effect Controls panel. You might try experimenting with simpler masks to get the hang of the workflow. Creating a single complicated mask is not a beginner-friendly technique to start with, unfortunately. 

Are you masking a human figure? It looks like you are. That may take multiple masks to control appropriately. While possible in Premiere Pro, multiple mask handling and masking (rotoscoping) human beings are more in motion design, and After Effects would be the better tool for that.

I hope we can help you achieve what you want, though.

Thanks,
Kevin