Legal basis: People's Republic of China (PRC) Tax Collection and Management Law.
Article 51 If a taxpayer overpays taxes, the tax authorities shall refund them immediately. If it is discovered within three years from the date of final settlement and payment of taxes, the tax authorities may be required to refund the overpaid taxes, plus interest on bank deposits for the same period. If the tax authorities verify it in time, they shall immediately return it and withdraw from the state treasury, and return it in accordance with the provisions of laws and administrative regulations on the administration of the state treasury.
Article 52 If the taxpayer or withholding agent fails to pay or underpays the tax due to the responsibility of the tax authorities, the tax authorities may require the taxpayer or withholding agent to pay back the tax within three years, but no overdue fine will be charged.