The level of high-quality openness is determined by the degree of economic openness, so this paper explores the impact of high-quality openness on China’s economic growth according to the degree of economic openness and analyzes the long-term equilibrium relationship and short-term dynamic adjustment process between high-quality openness and economic growth by using mathematical and statistical methods such as co-integration analysis and error correction model. An indicator system containing multiple dimensions such as trade openness, foreign cooperation, and real tariff rate is constructed, and China’s relevant data for the past 15 years are collected for empirical analysis. The research results show that there exists a long-term stable equilibrium relationship between economic growth and the indicators of economic openness, and every 1% increase in overall economic openness leads to a 0.48532% increase in GDP. In the short term, the openness of the Chinese economy has a minor impact on economic growth over the same period. Additionally, there is a unidirectional Granger causality between economic openness and China’s economic growth, i.e., economic openness can enhance economic growth, but economic growth is not the cause of economic openness. It indicates that high-quality openness can promote China’s economic growth.