Two conventional theories to explain gender-earning differentials, human capital theory and gender occupational segregation theory have both met challenges in the rising Chinese labor market. Using the JSnet 2009 data set, this study attempts to investigate the male-female earnings differential in China’s urban labor market with social capital perspective lens. Two research questions are examined. First, why does social capital affect earnings gap between genders in urban China’s labor market? Second, to what extent, after netting out the effects of all the other influential indicators, the earnings gap can be explained by different accesses to (capital deficit) and returns on social capital (return deficit) between genders. The improved Oaxaca-Blinder decomposition and quantile regression decomposition techniques are primarily used as statistical methods. It is found that after netting out the effects of other influential factors, like indicators of human capital and gender occupational segregation, social capital is the most crucial predictor of gender earnings gap in China’s urban labor market. Moreover, females’ social capital deficit and social capital return deficit simultaneously contribute to their earnings disadvantage in China’s urban labor market relative to their male counterparts.