Based on cross-section data worldwide and time series data in China, the essay is intended to make an analysis of the factors which have impacts on the ratio of public investment in education by using econometric models and then the future ratio may be predicted. Conclusions are as follows. First, the proportion of fiscal revenue to GDP (gross domestic products) is the most significant variable to predict the variance in the ratio of public investment in education in China. Second, experience in middle-income countries should be given top priority when international comparison is made. Third, the ratio of public investment in education in China will be close to 4% in 2010, and reach 4.4%-4.5% in 2020.