With the deepening of the “the Belt and Road” construction, China's water conservancy international engineering companies and the host country have an ever-expanding gap for international talents. The key to attract and retain international talents and make them have the intention to stay lies in providing them with international competitive and attractive environment. Based on field theory and commitment theory, according to the theoretical logic of “environment-attitude-behavior”, taking the regional talent attraction of the host country representing the environment of the host country as an external factor and the regional commitment reflecting the positive attitude of international talents towards the region as an individual factor, this paper explores the mechanism of the influence of regional talent attraction of the host country on talents' intention to stay through regional commitment. Based on the paired samples of 63 international water conservancy engineering project locations and 392 overseas employees of China's water conservancy international engineering companies, the cross-level analysis method is used to conduct empirical tests. The results show that regional talent attraction of the host country has a positive impact on talents' intention to stay, and this effect plays a role through the intermediary mechanism of regional commitment, which means that good host country environment and positive individual attitude are conducive to improving the intention of international talents to stay. This research enriches the content research of talents' intention to stay, and also provides a reference for China's water conservancy international engineering companies to formulate effective international talent retention measures in the construction of “the Belt and Road ”.