This paper proposes to study and analyze the factors affecting auto sale，based on traditional GRA and entropy weight method，conducts weighted analysis on the two methods，selects former five factors and then builds VAR model to deeply study the influence of various factors on auto sale. The results show that each factor is connected and coupled，among which the influence of GDP and steel output on auto sale is more significant，but with the increase of the time，the influence on auto sale is more remarkable.