you need prepare for the following documents:
1. Your valid actual passport. The passport must have at least six (6) months validity left before expiration and at least one blank page left in it.
2. One completed Visa Application Form affixed with one additional passport photo (black & white or color is acceptable).
3. Ivitation letter from authorized Chinese department, such as the Foreign Affaires Office, Committee of Foreign Economic Relations and Trade
4. residence permit of cambodia or valid visa of cambodia

The fee for one year multiple entry visa is US$90