Abstract: Introducing heterogeneous individuals and frictional investment market into the OLG model, we study the relationship between financial structure and economic growth from the perspective of the supply of funds. The results show that more and more individuals will invest in risk assets and pension funds with the economy growth, which means the size and the proportion of risk asset market and pension market will increase and that of the risk-free asset market will decrease. Besides, the development of risk asset market and pension market will promote economic growth, and cause the changes in financial structure.