Abstract: A mobile robot which includes a processor module, and a distance sensor, an auxiliary obstacle avoiding module, and an interacting module is disclosed. The distance sensor is configured to scan an operating space of the mobile robot to build an environmental map. The auxiliary obstacle avoiding module is configured to detect obstacle and cliff boundary in a sensing blind area of the distance sensor while the mobile robot is moving. Virtual obstacle information is input as needed into the environmental map by the interacting module to complete the environmental map and plan movement path for operation of the mobile robot according to the environmental map. The mobile robot can build up and gradually complete the environmental map of the operating space, and plan movement path of the mobile robot for operation according to the environmental map, thereby accurately avoiding obstacle, reaching target position successfully, saving time and energy. A navigating method for a mobile robot is further disclosed.