Abstract: Tax compliance agreement is a new and important enforcement approach which is used in many fields recently. However, there are different points about its nature and legality. From the current text of tax compliance agreement, the act of contract between tax authorities and enterprises cannot change the legal relationship. In fact, most terms of tax compliance agreement are just a duplicate from tax laws. Although tax compliance agreement's outward appearance is a contract, it cannot be treated as an administrative contract and just an administrative guidance. At the same time, although tax compliance agreement's basic principle is autonomy of will, it also must be carried out within the framework of the statutory taxation principle. Tax authorities and enterprises cannot change the legal relationship by agreement.