Six urban areas are classified using the land use vector data sets and natural zoning map of China from 1990 to 2000. The first grade urban area includes east Liaoning and east Shandong hill area,north China plain,middle Shandong hill area,Huaihe basin,middle and lower reaches of Yangtze river,Guangdong,Guangxi and Fujian mountain plain,north China hill area. The urban land percentage of these areas and the speed of urban expansion are higher. The urban expansion in these area takes up 71.47％ of total China and the loss of cropland takes up 69.88％ while north China plain is 24.54％ and Huaihe basin,middle and lower reaches of Yangtze river is 20.15％. The major source of urban land is derived from crop land and the percentage is 78.96％ while rural land is 10 .2％,forest land is 4.48％,water is 1.56％,construction land is 1.43％ and bare land is 0.77％. A great amount of cropland will be lost by the urban expansion and threat the grain safety in China.