Legal analysis: depending on the situation, the employer should pay social security for its employees within 30 days from the date of employment. If it is an internship, it is not necessary to buy social security.

Legal basis: Social Insurance Law of the People's Republic of China.

Article 57 An employing unit shall, within 30 days from the date of its establishment, apply to the local social insurance agency for social insurance registration with its business license, registration certificate or unit seal. The social insurance agency shall, within fifteen days from the date of receiving the application, examine it and issue a social insurance registration certificate. Where the social insurance registration items of the employing unit are changed or the employing unit is terminated according to law, it shall, within 30 days from the date of change or termination, go to the social insurance agency to handle the change or cancellation of social insurance registration. The market supervision and management department, the civil affairs department and the organization management organ shall timely inform the social insurance agency of the establishment and termination of the employing unit, and the public security organ shall timely inform the social insurance agency of the birth, death, household registration, transfer and cancellation of the individual.

Seventy-fourth social insurance agencies obtain the data needed for social insurance work through business handling, statistics and investigation, and the relevant units and individuals shall provide them in a timely and truthful manner. The social insurance agency shall establish a file for the employer in time, completely and accurately record the social insurance data such as personnel participating in social insurance and payment, and properly keep the original vouchers for registration and declaration and the accounting vouchers for payment and settlement. The social insurance agency shall timely, completely and accurately record the individual contributions to social insurance, the contributions paid by the employer, and the personal rights and interests records such as enjoying social insurance benefits, and regularly send the personal rights and interests records to me free of charge. Employers and individuals can inquire and check the records of payment and social insurance benefits from social insurance agencies free of charge, and ask social insurance agencies to provide social insurance consultation and other related services.