(a) X1 visa 

The X1 visa is issued to those who apply for long-term study in China. The visa is valid for 30 days after you enter China. You must apply to the international student office for a residence certificate within that  period before you can legally reside in China for a long time. Students are also required to provide health certificates issued by the Haikou entry-exit inspection and quarantine department before they can receive residence certificates.

(2) X2 visa 
The X2 visa is issued to persons applying for short-term study in China. The valid period of the X2 visa, or the number of days of residence allowed from the date of entry, will be marked on the visa page. For example, if you enter China on August 25 with an X2 visa valid for 90 days, you can stay until November 23 of that year.

(3) Residence Certificate 
International students who will study in China for more than 180 days need to apply for a residence certificate, the validity period of which is indicated on the residence certificate. Students can enter and leave China many times during the validity period of the residence certificate.

Remarks: Students who hold an X1 visa can apply for a residence permit. X2 visa can only be used for short-term study and cannot be converted into a residence permit (if you pay the tuition of one semester, you can only apply for an X2 visa, and if you pay the tuition of one year, you can apply for a residence permit of one year). Students are advised not to enter China too early, because you can only apply for an X2 visa and residence permit after you report to the school.

For information about the Chinese embassy/consulate in your country, please refer to the website of the Ministry of Foreign Affairs of China: http://www.fmprc.gov.cn/ 
For more information on visa issues, please refer to the China Consular Affairs Network:

http://cs.mfa.gov.cn/