Late payment fee is a certain percentage of late payment tax charged according to the number of days of late payment for taxpayers who do not pay tax according to the tax deadline. The provisions of the Tax Administration Law on the tax late payment system are slightly superficial, resulting in tax cases in which there is confusion in the enforcement of tax authorities and differences in the judiciary’s decisions. With the implementation of the new Administrative Compulsory Law, the nature of late payment and the upper limit of tax collection have been hotly debated. Based on the author’s own tax work experience and legal knowledge, this paper aims to clarify the legal basis for the collection of late payment fee and the upper limit of collection, in order to facilitate the grassroots tax enforcement.