Here is what I thought : I have already know the coordinates (x, y)of 4 points (or more )of the geometry plane, how can I successfully draw the geometry it in UE4? Is anybody know that? Thanks!

looks like your trying to make a procedural mesh in the engine. theres a bunch of resources on that topic just do a bit of googling. i googled it and came up with a short video that shows how to accomplish this. [Unreal Engine 4 Guide - Mesh generation]