I want to visit PRC for business purpose for the 1st time. what papers do I need?

You should apply for a M type one. Except for your passport (with a validity of more than six months and two blank pages at least), filled application form (2013) with a recent passport size photo, you have to provide the following documents:
1. invitation letter from your business partner. It should includes the following contents:
1). personal info of the applicant: Date of birth, name and sex.
2). visit details: reasons for coming, intended dates of arrival and departure, places to visit, relations with the inviter and financial sources.
3). the inviter's info: names of the inviter, tel, address, company stamp and signature of the corporation or owner of the company
2. a letter of explanation on the applicant's company.
3. other documents required by the embassy.

What do you ment by other doc. Pls specify.

Generally, the documents are enough. Sometimes, the embassy might ask some other documents. We don't know what they ask. They just ask for them according to your personal situation.