There's something wrong on my model

As I said there’s something wrong. I couldn’t get it. There’s something gray on the couch. There isn’t anything wrong in modelling and texturing. So can anyone help ?

Without a blend file, its going to be difficult to say anything…

I solved it. Thanks for the reply BiggR !

If you later do not want me to eat my hat… i’m almost ready to bet that you have 3 cushions. Check Outliner and even if one eye icon is greyed out unless camera’s icon is on you’ll get overlapping objects on render.

Next time either supply .blend or make sure your image shows maximum useful information. We do not want to see nice walls; we’d love to see close up what’s wrong. Do not crop user interface.