Focused on the generation and the status of the market demand gap, the quantitative analysis and study have important significance for solving the problem of over-investment and excess capacity in the Chinese car market. The quantitative research in car market often focus on the prediction of the demand for cars nowadays, while the research about the market demand gap for cars is less. In the study of the imbalance between supply and demand in foreign markets, scholars often analyze the imbalance between supply and demand in the market and the demand gap with the help of the disequilibrium econometric model. Through the disequilibrium econometric model estimation results, we found that the change of China's car market demand gap can be divided into three stages: the rising stage, the declining stage and the equilibrium stage. The equilibrium of supply and demand in China's auto market is gradually building.