Is there any way to make the particles always face camera?
Hi Mayaping, you have 2 solutions :
Move your particles emmiter to follow your camera (or character)
Take a renderToTexture Camera, place it in front of your emmiter.
Behind the emmiter place a surface (or cube) with a black LIT material.
Make a HUD material with the renderToTexture texture and use the black for opacity.
Use this last material on an image on the HUD.
Better tutorial here (My english is bad !) : Render 3D objects in UMG Widget/HUD | EngineUnreal