This article is based on the trade between the countries along the Belt and Road from 1998 to 2017. It first measures and compares the development and changes of their terms of trade, and then uses the dynamic panel system GMM method to test the specific impact of product diversification on the terms of trade. The results show that the terms of trade of the countries along the route have generally been good in recent years. Most of the countries along the route have better terms of trade based on changes in product types than traditional methods, but the differences between different countries are large. Product diversification can improve the terms of trade, but differentces exist. The effect of diversified products on the improvement of terms of trade also has certain differences. In addition, technological progress and economic growth have certain effects on improving the terms of trade. In the future, China must not only innovate growth methods to continuously enhance our economic strength, improve trade interests, and enhance international status, but also solidly promote economic and trade cooperation with countries along the Belt and Road, and pay more attention to adapting to national conditions to achieve common progress.