I am a Pakistani national, have a company in China and my visa is Z category (Chinese Work Visa). I want to travel to Taiwan for a business trip. How I can get the visa?
Are you currently residing in China? I wouldn't rely on your Chinese work visa to get you into Taiwan. You must get a visitor visa to enter Taiwan as there is no landing visa for Pakistan nationals. Previously Pakistan nationals acquired visas from Thailand, but I've heard a rumor they are no longer issuing for Pakistan nationals (if anyone can confirm this, that would be helpful). I would recommend you try and call the TECO in Hong Kong.
Taiwan Info has information on visas and prices. A simple phone call can get you plenty of information.
Also, be sure to read the BOCA information on visas.