chinese embassy required documents for business visit visa

The requirements for business visa application for Sri Lanka nationals:
1. your sri lanka passport remaining to be valid for at least 6 months from the date of application and with sufficient blank visa pages.
2. One completed Visa Application Form with a recently-taken passport photo (only 2 inch * 2 inch color photo with light background like light blue and white is acceptable);
The handwritten visa application form is not accepted, please fill in the form on computer and then print it out
3. the invitation letter from a host company or factory or unit in China
4. Invitation Letter of Duly Authorized Unit or Confirmation Letter of Invitation issued by Foreign Affairs Office or Bureau of Foreign Trade and Economic Cooperation