I'm from Yuechi County, Sichuan Province, can I buy social security in Wanyuan?

Yes, you can buy it in Wanyuan if you work there again.

The Administrative Regulations on the Declaration and Payment of Social Insurance Premiums require that employers should apply for social insurance registration for their employees and declare the payment of social insurance premiums within 30 days from the date of employment. If the employer fails to register for social insurance, the social insurance organization shall approve the social insurance premiums to be paid by the employer.

For some employers do not pay social insurance premiums in full and on time, the provisions of the social insurance agency shall order them to pay or make up the full amount, and from the date of arrears of 0.5 per cent of the late payment fee per day; overdue payment is still not paid by the social insurance administrative department of the amount of arrears of more than one times the amount of fines less than three times.