[Objective] We attempts to expound the really important function of farmer's human capital in terms of improving land output from the angle of farmer's human capital stock for the first time in order to provide a theoretical basis for reasonable and effective utilization of land resources. [Methods] We analyzed the contribution of farmer's human capital stock in terms of improving land output by using the analyzing tools: revenue model and Lucas Spillover model, SPSS 20.0 software, time-series data(statistical data of Gansu Province in 2002-2012). [Results] In Gansu Province, the rates of the contribution and the influence of the farmer's human capital to land output were 89.46% and 10.98%, and these of material capital to land output were 8.26% and 1.01%, which meant that the contribution rate of human capital to land output was far higher than that of material capital. [Conclusion] Properly developing and employing human capital will make a great difference on improving land output.