The purpose of this article is to re-estimate China s agricultural surplus labor. Our estimation is based on three prevalent methods including classical, neoclassical and standard structure comparing methods. Different from other researchers, we pay attention to not only the total amount of surplus labor but also its distribution among different provinces and districts. By comparing the results from the different methods, we conclude that the classical method is the most creditable. In order to make them more reasonable, we modified the three methods. The results show that there are about 40 million agricultural surplus labor in China currently.