17.4 km. According to Baidu map, the distance from Changhai County to Zhangzidao is 17.4 km, passing through Changhai East Road and Lijiang-Qiaoxian Line. Changhai County is a county under the jurisdiction of Dalian City, Liaoning Province, located in Changshan Islands, an extension of Changbai Mountain Range, and Zhangzi Island is located at the southernmost tip of Changshan Islands in Dalian City, Liaoning Province.