From the concept of external cost of transport,the paper analyzes the significance of internalization of external costs.Utilizing the car's travel demand function,average travel cost and social marginal function,the paper takes the society marginal cost as the reference benchmark and explores the impact of internalization of external costs on transport behaviors according three kind complexion.Furthermore,it discusses impacts of the substitution effect and the income effect of the practical internalization measurements.The conclusions indicates that internalization of car-use external costs is advantageous to seeking a fair and also sustainable transport system due to existence of the income effect and the substitution effect,and can achieve a real priority for public transportation.