This paper conducts an empirical study on trade efficiency and trade potential of China and countries along the Belt and Road by introducing the stochastic frontier analysis into trade gravity model. Based on the stochastic frontier gravity model, determinants of bilateral trade flows are analyzed, trade potential is measured and trade efficiency is evaluated. Component factors of trade non-efficiency are explored through setting up a trade non-efficiency model which taking into account the tariff, trade facilitation, transport facilitation, economic liberalization and FTA factors. According to the empirical research results, strategy of improving trade efficiency and fulfill trade potential are proposed.