The effect factors of private car inventory is analysised in this paper, the dominance relations among the effect factors of private car inventory is determined by grey system theory.

The mathematical model for the prediction of total number of private cars was proposed using a grey system theory.

Described is the determination of the renewal of the present number of cars with the calculation and prediction method of the "Rolling Stock Operation Financial Balance Table".

The forecast of the vehicle ownership has the direct significance to the urban transportation development direction,by analyzing the effect to the urban vehicle ownership;the author has found the urban population,GDP,public transit service level,etc.

The quick increase of vehicle ownership in China is not only stimulated by the increasing income level,but also affected by the enlarged inequality of income.

There is a close relationship between vehicle population and development of society and economy.

Avoiding the shortcomings of traditional BP algorithm, the authors adopt genetic algorithm to optimize the connection weight of BP network in forecasting the long-term vehicle population in China.

This paper presents the status of vehicle pollution in China and its evolution by the year 2000 and 2010 through the consideration of vehicle population,oil consumption,pollutant emissions,and air quality in major cities.