I am from pakistan and want to visit hong kong.

You need to apply for HK visa for that. First, you need to provide copy of passport, the application form affixed with a passport-style photo, proof of your financial support, transportation and accommodation arrangement, and your travel plan and residence permit in China. Then, submit the application to Beijing office of HK government.

Which kind of financial proof? Any bank statement?? Oif bank statement then how much money is required?

Bank statement will be okay. There is no exact requirement for how much you should provide. Usually, you should prepare at least USD100 per day.