The Civil Code does not inherit the provisions of Article 142 of the General Provisions of Civil Law on the application of international treaties, resulting in the legal basis of the application of CISG in foreign commercial trials. After investigating the application of CISG after the implementation of the Civil Code, this paper finds that there are situations in judicial practice where CISG is not wanted or dare not be used, leading to the inconsistency in the selection of applicable laws for foreign-related commercial trials. However, the international law principle of “treaties must be complied with” requires that CISG should be applied preferentially if the conditions are met. The recognition of foreign court decisions and the improvement of its enforcement effect also need the correct application of CISG. In addition, there are clear requirements on the priority application of CISG in Chinese legislative evolution. In order to perfect the legal application procedure of our foreign-related commercial trials, for the one part, the preferential application rules of CISG in Chinese foreign-related civil and commercial trials can be clarified by means of legislation and judicial interpretation of international private law; for the other part, the application procedure steps of CISG can be clarified in the form of guiding cases, and the professional ability of judges in foreign-related trials can be improved by regular professional training, so as to reduce the uncertainty of judges in the application of CISG and enhance the uniformity of law application in foreign-related commercial trials.