This article first reviews the previous research on the relationship between economic growth and financial development. Secondly, it reviews the financial reform process of China's 40th anniversary of reform and opening up and it analyzed the economic growth of forty years. Before the reform and opening up, China was a completely planned economic system, and economic growth was very unstable. Per capita GDP growth was often negative. After the reform and opening up in 1978, China's economy grew at a high speed and has stabilized in recent years. The growth rate of the added value of the financial industry is similar to that of the economic growth rate, but the fluctuation is even greater. At the end of the second chapter, it analyzes several typical characteristics of China's financial industry: bank financing dominates, M2/GDP ratio is high, and the financial industry's added value is high. The third chapter selects the financial interrelation rate, financial efficiency and the development of the stock market as financial indicators, per capita GDP as an economic indicator, and uses these indicators to analyze the relationship between financial development and economic growth. The conclusion is: financial interrelation rate and economic growth promote each other; there is no relationship between financial efficiency and economic growth; economic growth promotes the development of the stock market, but the stock market does not promote economic growth. China's financial deepening is the reason for China's economic growth. The growth of China's economy is also the reason for China's financial deepening. They have a long-term stable relationship.