Abstract: Base on the geological hazard risk assessment index system of the island, make full use of fuzzy mathematics method, we have evaluated the geological hazard risk of Changxing island. The result showed that the high-risk area is 9.95%, the risk area is 14.00% and low-risking area is 76.05%. In addition to the large centralized distribution of the high-risk area and the risk area, it also showed that Changxing island had a patchy distribution around the coastal zone of the island, which cause by the combination of different natural geological environment and socio-economic factors in Changxing island.