Abstract: Intelligent service robot has become a research hotspot in the field of robots at home and abroad and the results of the researches on intelligent service robots have gradually entered people's daily life thanks to the push from artificial intelligence technology. As an important intelligent feature of intelligent service robots, autonomous mobility is the key to ensure practical application of intelligent service robots. Based on ROS, the architecture of autonomous mobile robots was studied and the hardware and software architecture design of autonomous mobile robots was also proposed. Based on the hardware and software architecture, SLAM-based map construction, positioning and navigation technologies were studied. Furthermore, the framework of the navigation system was designed and an improved A^* path search algorithm for navigation path planning was proposed and verified by tests conducted at the railway passenger station. The test results showed that the efficiency of the improved A^* path search algorithm was about 30% higher than that of the traditional A^* path search algorithm so as to help reduce the search time and complexity and enhance the optimization efficiency of search path, meeting the application requirements of positioning, navigation and path planning of mobile robots at railway passenger stations.