I think you want to apply for a multiple F visa, but the requirements are very strict:

(1) The applicant has a visa notification issued by the authorized Chinese unit, which specifies the validity, number of entries and duration of stay for the visa application; or

(2) The applicant has made an investment in China. Please submit the original and photocopy of the Chinese business license carrying the name of the applicant (The original one will be returned after checking); or

(3) The applicant is in a position of management in a company which has a subsidiary in China. Please submit an application letter from the company and an invitation letter from the Chinese subsidiary company; or

(4) The applicant has visited China more than twice with the (F) visa within the past 12 months. Please submit a copy of the visa and an invitation letter from China; or

(5) The applicant need to visit China frequently in order to execute contracts signed with a Chinese company. Please submit the original and photocopy of the contract (The original one will be returned after checking).