Multi-dimensions and various mechanism of social mobility can be understood by an analysisof the role of assortative mating.  Based on the data of China General Social Survey in 2006 (CGSS 2006) and by employing the Probit model as well as the Binary Endogenous Ｒegressor Probit model，this paper explores changes in features and affecting factors of assortative mating of rural females over time. This paper has come up with several profound findings. First，for rural females，marriage produces very limited effects on their upward social mobility. Second，achieved factors generate more remarkable effects on the hypergamy opportunity compared with birth-ascribed factors. Third，hukou conversion from the rural to urban status，an indication of social mobility，impacts positively on the possibility of hypergamy. Fourth，the influence of the urbanhukou on social mobility has been gradually weakened with changes in socioeconomic meanings of thehukou categories. This paper also demonstrates that the conceptual and practical meanings of social mobility by hypergamy vary under different historical backgrounds.