In view of the relationship between the price level of the real economy from investment，production to consumption，this paper used the method of factor analysis model to extract comprehensive public factors from all kinds of price indices in China，and to reflect the overall price level through this factor. The results show that there is a strong correlation between the various price indexes，so the common factor is effective. At the same time，compared with the single price index，the common factor can more effectively and comprehensively reflect the changes of price in the fields of production，consumption and investment. By this common factor，we can provide more scientific reference for the level of inflation.