My supervisor does not believe my abilities I am a third year PhD student, I have got a problem with my supervisor, that I think I cannot continue working with him.
My problem is that he keeps insisting this fact that I need to switch from PhD to Msc. He thinks always negatively about my personality and my abilities. My supervisor was nearly 1 year on sabbatical, and I had no support during 1 year, and this is only 4 months that he has come back from sabbatical. Although he admits that I had good progress, but he keeps treating me negatively. I have reached to this conclusion that I need to change my supervisor. I cannot work with a supervisor who keeps thinking about me negatively. How should I deal with this?
It's may not be in your best interests to continue working with this supervisor.  If you can find another supervisor, then it might be wise to switch, but you'll have to consider how changing dissertation topics might slow down your progress.  

Of course it's possible that you really are performing poorly.  If other faculty in the department are disinterested in supervising you, then that would be a strong indication that you aren't doing well in the program.