Is it legal to buy social security after becoming a full member?

Legal analysis: illegal. You should also buy insurance during the probation period. The probation period also means that the employer and the employee have established a labor relationship. Since the establishment of labor relations, it is necessary to pay social insurance for workers, which is the legal responsibility and obligation of the employer. Otherwise, once the employee applies for labor arbitration, the enterprise will lose, and in addition to making up the payment, it may also be subject to administrative punishment by the social security labor inspection department.

Legal basis: Article 58 of People's Republic of China (PRC) Social Insurance Law. The employing unit shall handle 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.