Abstract: There have been seven civil airports distributed in Nanjing, Wuxi, Changzhou, Nantong, Xuzhou and Lianyungang in Jiangsu Province, which was called "'7’civil airport" layout.With the rapid development of transport capacity, the scale and quantity of civil airports is being improved. Based on this background, construction of two new civil airports in Huaian and Yangzhou, both of which located in Jiangsu Province had been carried out. Therefore, the layout of "‘7+2’civil airport "would be come into being in Jiangsu Province. In order to make a quantitative study about civil airports and service capability in Jiangsu Province, this paper firstly mainly used the Spatial analyst module functions of AarGIS to do a empirical research about accessibility of civil airport in Jiangsu Province based on the highway network structure and calculations of optimal road routes and time to civil airports of Jiangsu Province, which generated accessibility diffusion graph and service area map before and after the formation of the "‘7+2’civil airport". Then a comparison and analysis of the graph and chart was made and analyzed, and the result showed that the overall accessibility of existing civil airports in Jiangsu Province was fairly good basically. However, as to the regional distribution, the accessibility diffusion graph took on a laver structure taking civil airports as the center. Currently the accessibility time of 88.5% of Jiangsu Province area was within 1.5 h, but the internal difference was also obvious. The accessibility of civil airports in southern Jiangsu was much better, while it was still much worse in the inland area of northern Jiangsu, because there was no civil airport. The size of service area of civil airport in Jiangsu Province was large in the north and small in the south. When the layout of "‘7+2’ civil airport" were formed, it would greatly improve the accessibility of civil airport in the inland area of north Jiangsu, and the size of service areas was reduced with different degree, and the proportion of better accessibility area was higher obviously, while the proportion of worse accessibility area tended to go down. And then,an approximate calculation about the potential service capability of civil airports which were classified as three grades was made combined with some related factors, such as population, GDP, per capita GDP, per capita disposable income and civil airport grade. The service capability of Nanjing civil airport which belonged to the first class had absolute priority in the layout of "‘7+2’ civil airport "in Jiangsu Province, and the civil airports of Wuxi,Changzhou and Xuzhou belonged to the second class, and the rest of civil airports belonged to the third class. Finally, the problems and shortage existing in the civil airports in the different grades combined with economy and accessibility were analyzed, and some corresponding optimization measures were brought forward. Furthermore, it would provide theoretical basis for the distribution, efficiency improvement and balanced development of civil airport, which would have great theoretical and practical significance.