Thanks.

From the screen shot I can not explain or figure out what might be going on I do not see a reason why this would be happening

I'm not sure either, but I'm going to guess it's because you still have the object selected after you applied the Subdivision Surface modifier. I usually deselect the object once the modifier has been applied, so my mesh usually turns what looks like solid black. The reason is because, once subdivided, there are so many more polys than there were before the subdivision, and I usually have to zoom in a bit closer to see the mesh better.

I can only assume the same is true of the UV layout, because it turns an orange/red color when the object is selected in the Edit mode window.

Thanks.But I find uv layout can do texture map. And I get uv layout before applying Subdivision Surface,after Subdivision Surface I make uv layout again,so it is red.

Whilst you had all the vertices selected you may have hit "P" which pins the selected vertices. This is what turns all the vertices red. To fix this select all the vertices again and press Alt+P. Only solution I can think of based on the picture you provided.

OMG, of course!! Thanks keppel, I totally forgot they turn red when pinned. I don't do that very often, so it's been a long time, and I totally forgot about it. The only thing I could think of was they were selected, but that just turns the UVs orange, not red as in atpo's screenshot.

Thanks.