Improving the intensity of service of a product and needs satisfaction of product per unit and reducing environ- mental impact resulting from needs satisfaction per unit will enable us to provide the same needs satisfaction with fewer products and less impact of environmental life cycle,thus improving economic ecological efficiency of a product.This paper calculates the economic ecological efficiency of car sharing in Netherlands and conducts an empirical study on in- formal car sharing in Beijing.Beijing Government should adopt certain policies to regulate current booming informal car sharing and encourage formal car sharing services across the city.