Base on the Grossman and Helpman’s Two-stage Negotiation Model，this article build a fragmentation partner searching model to study the determinates of keeping on smoothly production，and then a Heckman Sample Selection model was used to give a empirical estimation. The result suggestion that the coincidence of two counties’ comparative advantage is one of the most important determinates that affects the fragmentation connection of two countries and the technology gap of these two countries had generally promoted the fragmentation connection of countries，and a appropriate technology gap do this better.