Can I duplicating mesh with a new material.

[Langlae]

If I have a material-filled mesh,duplicate it,can I fill a new one with other material?
If I can't, what should I do?

I just want to make a group of cycle candy,like a panel of grass.

[mAlkAv!An]

Yes you can. Each static mesh actor in the level can reference a different material. Easiest way is to drag and drop a material from the content browser onto your mesh in the scene.
For Meshes with multiple materials, open actor properties (F4) and then go to Static Mesh Component -> Rendering -> Materials