Legal analysis: not illegal. According to the regulations, the degree-conferring unit may revoke the degree it has awarded if it finds any serious violation of the provisions of this Ordinance, such as fraud or forgery, after reconsideration by academic degree evaluation committee. Therefore, writing papers on behalf of others undermines the degree-granting system. But this is still a rule, which has not yet risen to the legal level, so criminal trials cannot be conducted on this basis. Whether there are legal norms in this field is still controversial. As far as the present situation is concerned, it is not illegal to write papers on behalf of others.

Legal basis: Article 17 of the Regulations on Academic Degrees in People's Republic of China (PRC). If the degree-conferring unit finds that the degree-conferring seriously violates the provisions of these regulations, it may be revoked after reconsideration by academic degree evaluation committee.