Abstract: By referring to the ecosystem service value coefficients proposed by COSTANZA and XIE Gao-di,an ecosystem service value coefficient was developed which is applicable to urban ecosystems. And based on the land use change/cover (LUCC) data of Chongqing proper in the year of 1993,2000,and 2004,ecosystem service value of the city was calculated. Results show that since 1997 when Chongqing became a municipality directly under the Central Government,large areas of farmland and forest land were alienated for urban construction,causing fall in its urban ecosystem service value by 31.3%,from 564.75 million yuan in 1993 to 387.71 million yuan in 2004. The effect of the changes in the ecosystem service value coefficient on the total urban ecosystem service value of Chongqing is not flexible enough. The impact of the change in water surface and woodland area on the total urban ecosystem service value of Chongqing is significant.