I am trying to display a video from a remote video camera in IP Phone 7985,but I do not have any clue, may I ask what can be done, thank you!

I'm afraid there's no way.. I had a lengthy case on this and it boils down to the phone not supporting video outside of a call context.
Our client wanted to do video surveillance via the phone and probably would've gotten a bunch of 7985s if it were possible.

Turns out though the video server just serves MJPEG so essentially a webbrowser would do - however there we enter another limitation of the phones - they don't do MJPEG and if you serve separate JPEG images, the refresh interval is 1 second and it takes a while to load so you'll get somewhere between 2 and 3 seconds per image which means it's more stills than video.