What are the best colleges in USA that can accept a mechanical background student to study cs in United States (with good acceptance rate) Note : I have one year of experience in TCS as engineer?

The best one-year M.S. in C.S. programs currently are:

M.E. in C.S. - MIT
MSc. in C.S. - Stanford University
MSc. in C.S. - Carnegie Mellon University
MSc. in C.S. - University of California: Berkeley
MSc. in Computer Engineering - New York University
MSc. in Computer Science Engineering - University of Washington
MSc. in Scientific Computing - University of Pennsylvania
While MIT and Berkeley are widely known for their specialized C.S. programs, other major universities are also excellent. They are more student-oriented C.S. programs. In simpler terms, it will allow you to add more qualifications or apply to a broader scope of professions. C.S. masters at MIT, Berkeley or, let's say, ETH Zurich are more keen programs. Select them if you are in for the whole deep academic experience. I.T. and engineering are some of the most interlinked sectors with C.S. Therefore, if you choose to go for a different relevant field, you have tons of options.

 

Before opting for a one-year program in the USA, consider its limitations. Most of the one-year computer science masters programs are terminal degrees. Terminal degrees are pretty standard. However, they only let you out of a few career choices. Like, after obtaining this degree, you will not be eligible to pursue a PhD.  As the course duration is so low, the programs are not heavily research-focused. Also, there are a few focused career options that you will not be able to pursue. And even if you do somehow manage to get in, it will require extensive deep knowledge on relevant subjects.