How can i resolve this problem?
-Model was imported
Blend: http://www.pasteall.org/blend/42835
Your blend file does not show your screenshot !
Opening your blend file you have a multitude of separate objects making up the model (Why?) and no subsurf modifiers as shown in your screenshot. Supply a proper blend file
You need to join all the objects into one (select objects then Ctrl+J) and then remove duplicate vertices (W / remove Doubles)
Where did you import it from ? What format, what settings ?
Subsurf is not subsurface but subdivision surface, and your model structure is not suitable for it in any way other than getting/making a structure that is.