Hello sir i m from nepal and m student in s.korea i want to visit hk for tourist purpose.

You need to prepare these documents:
1. Copy of your passport
2. The application form with a passport-style photo glued
3. Proof of your financial support (you should prepare at least USD 100 per day)
4. Transportation and accommodation arrangement
5. Your travel plan to HK
6. Your residence permit in Korea
And then submit the application to the embassy of PRC in Korea to apply for it. Or post it to HK immigration department directly.
Here is the postal address:
Receipt and Despatch Sub-unit
HK Immigration Department
2/F, Immigration Tower
7 Gloucester Road
Wan Chai, HK

Thanks. Lot... Do i need some sponser or guranty from hk permanent card holder ???

A sponsor is not necessary. But if you have a sponsor, it will help you with your application.