Nowadays,with the rapid growth of economy,the effect of consumption on economic growth is becoming weak.Chinese scholars have made some explanation on it,but it is not satisfied.However,through studying the consumption function and establishing model,analyzing the consumption by income gap,the evolution process of resident income level,we can get a conclusion that the consumption expenditure is both disciplinary and uncertain.This provides not only a new viewpoint of recognizing our consumption but also could gives some reference for making consumption policy.