Abstract: Based on the school attainments, sectors, and regions distribution of questionnaire, there are a few defects lie in working experience square variable of human capital earning equation. According to the relation between working experience and earning of questionnaire, referring to the theory of expansion of human capital earning equation that is advanced by Murphy and Welch, by means of adding the working experience high-order terms into a standard Mincer earning equation, a significantly better fit for earning equation is yielded, the results reveal that the earning equation including a working experience cubic term is the bestchoice.