As a primary means of social security system, pension can smooth income and balance welfare level as well as prompt changes in residents’ consumption decisions. In addition, the aging of population also has an impact on pension system, which further affects residents’ consumption. The study of the effects of population structure and pension on the consumption of residents is of great significance to the expansion of domestic demand and the reform of pension system. Upon constructing an OLG model, this paper first carries out a theoretical analysis of the effects of population structure and the development of pension on residents’ consumption, and then conducts an empirical study using the provincial data between 2002 and 2015. Results show that the increase in pension has significantly positive effects on the consumption of urban residents and this relationship is further affected by the changes in population structure.