is it possible go to huangshan from hangzhou and stay over one night.comeback next day to hangzhou?

There is no direct train from Hangzhou to Huangshan. You may take train from Hangzhou to Suzhou(around 2 hours) first, then go to Huangshan(around 10.5 hours) by train. Alternatively, you can take bus at West Station from Hangzhou to Huangshan directly. And yes, stay in Huangshan city at night is no problem, but 2 days is too tight for you.

There are buses you can take to go to Huangshan, it takes about 3 hours