M.S. Granovetter’s hypothesis of “strong tie” and “weak tie” has been used in researching on the rural migrants in China. This paper argues that the patterns of social interaction in traditional China are unavailable to be analyzed with the concepts in pairs theoretically. Based on the statistics and interview materials, most of the rural migrants having jobs are favored with their ingroups. In order to explain these phenomena, the concepts of “strong trust” and “weak trust” are constructed. Compared with the two different concepts in pairs, “weak tie” is suitable for explaining the vertical and horizontal mobility, and the “strong trust” can explain why so many peasant workers from one village or one place are working in the same cities, communities or enterprises.
