Abstract: Since the reform of the tax system, the taxation administration departments at every level have assigned" taxation tasks", the quota of which was even linked to the political future of taxation officials. The tax farming system, had placed the tax law in a subordinate position, conflicts with the concept of rule of law, and impedes the process of taxation legalization in China. The analyses of predatory rule theory and contract theory help to sort out the reasons and disadvantages of the long term existence of tax farming system. To get rid of the plight of tax farming, it is necessary to change the existing mentality of tax-farming, and to set up the concept of statutory taxation at every level of taxation practice. It is also necessary to further improve the legal system of fiscal taxation, to enhance the fiscal constraints on public budget, to reform the existing taxation administrative system, and to protect the taxpayers' rights in order to fully realize legalization in taxation practice in China.

Key words: tax tasks, contract theory, predatory rule, tax farming, the principle of statutory taxation, tax legal relationship, tax law