In this report，through repeated comparison and calculation it is put forward that the national absolute standard for middle-income groups in China is that the per capita annual disposable income is 31000-78000 Yuan，and that the annual wage income per each wage laborer should reach 50000-125000 Yuan（it is the absolute price in 2015）. The middle income standards in megalopolises such as Beijing and Shanghai are determined as twice as the national standard. The size of middle-income groups in China is continuously expanding，currently accounting for approximate 25% of gross population and mainly concentrating in towns. Compared with the developed countries，the size of middle-income groups in China is smaller，the income level is not high，the pressure from expenditure is larger，the income source is single，the stability is weaker；and the distribution is unbalanced between urban and rural areas，industries and groups. The reasons to restrict the growth and development of middle-income groups are complex. It is necessary to advance the construction of factor market and property income distribution system through increasing the labor remuneration and resident income ratio，perfect the staff wage growth mechanism，promote the reform of the distribution system of government enterprises，and encourage the exploration of participation and distribution methods of technology and skill factors，improve the quality of laborers and human capital，and make better use of the underpinning，guidance and regulation functions in the field of primary distribution and redistribution，and guide and promote the development and expansion of middle-income groups.