How to divide the robustness test samples of undergraduate graduation thesis? Zhou Jingkui (20 19) found that with the improvement of agricultural productivity, rural families tend to invest in education, which in turn promotes the accumulation of family human capital. In this paper, the author first uses family education expenditure and family tuition and fees expenditure to measure education investment. In the next chapter of robustness test, the author replaces the explained variable with the proportion of household education expenditure to household income in that year, and investigates the influence of agricultural productivity on the proportion of education expenditure, further verifying the robustness of the influence of agricultural productivity on human capital investment.