May i know what's the documents required for application for multiple entry validity of one year?

It depends on your purpose of visit, so could you please tell me why are you visiting China?

I'm visiting my company's subsidiary for audit purpose, 2 weeks per visit. But my company is singapore company.

Are you applying it from Malaysia? And are you the citizen of which country? Where do you live now?

I'm malaysian citizen, i wanted to apply in malaysia, working in singapore.

JW, you actually can apply in Singapore as long as you have valid resident permit for employment there. Anyway, you can also apply in Malaysia too. You'd better apply for a M type. Apart from your passport, application form, recent six months passport photo, you should provide the invitation letter from your subsidiary company in China.