Do I need a residence permit to buy social security?

Legal analysis: you don't need a residence permit, just an ID card.

Legal basis: Article 58 of the Social Insurance Law of People's Republic of China (PRC) stipulates that the employer shall apply to the social insurance agency for social insurance registration for employees within 30 days from the date of employment. If the social insurance has not been registered, the social insurance agency shall verify the social insurance premium it should pay. Employees-free individual industrial and commercial households who voluntarily participate in social insurance, part-time employees who do not participate in social insurance in the employing unit and other flexible employees shall apply to the social insurance agency for social insurance registration. The state establishes a national unified personal social security number. Personal social security number is a citizen's identity number.