This article is based on the concept of cooperation in trade facilitation proposed by the Belt and Road Initiative, and demonstrates in detail the importance of customs cooperation in promoting trade facilitation. It provides an analysis of the importance of the connection between the existing legal system of international customs cooperation and the customs cooperation agreements of countries along the Belt and Road. It confirms the positive effect of the current bilateral customs cooperation and China’s practice. Then, based on a series of severe problems encountered in actual cooperation, it explains in detail the reasons why international customs cooperation needs to be updated. Finally, based on the existing problems of international customs cooperation along the Belt and Road, the article elaborates on the status quo of the countries along the route, emphasizes the importance of establishing a reasonable and effective legal operation mechanism and proposes solutions to improve the feasibility of international customs cooperation.