Abstract: The purposes of the uniform law of international commercial treaties determine their legal rules of preemptive application to domestic law. Taking the United Nations Convention on Contracts for the International Sale of Goods(CISG) as a typical example， its preemptive application rules have a clear legal basis in international law. While on domestic law level， how to deal with the legal conflicts between international commercial treaties and domestic law， directly affects the effect and degree of the judges' actual application of international commercial treaties. The main contracting parties of the Convention have implemented the preemptive application of the Convention through different legal paths based on their own constitutional， legislative， judicial and legal principles. Nowadays there is still scattered and chaotic application of Convention in judicial practice in China， so it is urgent to clarify the relationship between international commercial treaties and domestic law by strengthening the supply of legislation and judicial guidance.

Key words: CISG, uniform law, preemptive application, legal models