By distinguishing the basic concepts of working- age population, labor force participation population and employed population, this paper discusses the methods of employment research, including statistical decomposition, standardization, and life table techniques, and the related measurement difficulties. Using data from the census, 1% population sampling survey and employment survey of China, this paper examines the employment situation and the trend of Chinese labor employment. The research finds that the mode of employment has significant changed with the increase of education. The participation rate of labor force has decreased by more than 8 percentiles from 2000 to 2018. Along with the increase of education and the change of age mode of employment, both the total economic activity rate and the work life expectancy have declined. The work life expectancy at age 16 is about 31.86 years in 2015, which is 6.2 years shorter than that in 2000. The portion of the work life in life expectancy decreases from 64.33% in 2000 to 48.31% in 2015. Although China’s labor force is aging and the labor supply decreases, the employment problem for younger labor force is still very severe, especially when those aged 18- 24 are concerned.