Mr.nguyen anh, you should prepare the following documents:
1. One completely filled out visa application form. No item should be blank .

2. One recently taken 2X2 inch photo showing entire face and without a hat on. Please affix the photo to the application form.

3. Original passport with at least 2 blank visa pages and valid for at least 6 months beyond the date of application.

4. Round trip airline ticket and hotel reservation.

5. Singapore Student Pass and its copy

6. An approval notice from China Tibet Tourism Bureau is required if you intend to travel to the Tibet Autonomous Region (Telephone number for the Tourism Bureau: 86-891-6834313, fax number: 86-891-6834632). You'd better contact a travel agency in China and ask it to get the Tibet Entry Permit for you. Please don't declare that you will visit Tibet on the Visa Application Form. Then you will easy to get a China visa.