Abstract: In China, the current river crab culture mainly depends on human labor, which brings some problems such as aquatic plant cleaning difficulty, nonuniform feeding and high labor cost. In order to solve the problems above, this paper proposed a multi-functional automatic river crab culture operation boat based on ARM (advanced RISC machine) and GPS/INS (global positioning system/inertial navigation system) integrated navigation. The system was mainly composed of ARM controller, GPS/INS integrated navigation devices, GPRS (general packet radio service) communication device, aquatic plant cleaning device, automatic feeding device and paddle wheel driving device. In automatic navigation mode, the ARM controller firstly received and processed the navigation data including position, course and speed from the GPS/INS devices. PWM (pulse width modulation) module and GPIO (general purpose input output) module were called to control the boat sailing, aquatic plant cleaning and automatic feeding simultaneously. The host computer communicated with the ARM controller via GPRS device to monitor the real-time operating status of the ship borne subsystem remotely. In order to simplify the complexity of the traditional calculation method of channel position based on finite target points and reduce channel deviation error of the boat, this paper proposed a new calculation method based on real-time inserting points. This method calculated the current target position of the boat real-timely according to the position of the boat and the turning points of current channel. A new turning and channel switching strategy was also presented in this paper to improve the boat work efficiency and prevent the boat from deviating from the channel because of the high speed. Considering the movement characteristics such as non-linearity, big delay and underdamping of the boat, the course-speed dual-loop control algorithm was designed based on fuzzy PID (proportion integration differentiation). In order to enhance the stability and portability of the system, the ship borne subsystem was designed based on embedded Linux operating system, and the monitoring program of host computer was developed based on Visual Studio 2010 platform and SQL (structured query language) Server 2008 database. With the purpose of demonstrating the effectiveness of the proposed system, the speed response and automatic navigation tests were performed in Jiangsu University in September 2015. In the speed response test, the target speed of the boat was set to 35 cm/s and the host computer would record and display the speed response curve of the boat from the stagnation to the target speed. Results showed that the speed overshoot was no more than 5% and the steady-state error could be kept within 3%. The boat responded quickly and it could greatly meet the speed regulation requirements. In the automatic navigation test, the boat was initially driven by manual control to obtain the position of 4 turning points of channel. After that, the automatic navigation tests based on finite target point and real-time inserting point method were carried out respectively. The host computer would record and display the position and channel deviation error of the boat during the test. Results showed that the maximal channel deviation errors based on finite point method at corner and straight were 2.12 and 1.52 m respectively while the maximal channel deviation errors were 0.36 and 0.09 m based on real-time inserting point method. The maximal channel deviation error based on real-time inserting point method decreased by 83.02% and 94.08% respectively compared with that based on finite point method. Through the analysis above we can see the accuracy of automatic navigation system has been fully improved. The multi-functional automatic river crab culture operation boat has the advantages of high work efficiency and low labor cost and the research can be considered as an efficient reference in river crab culture in the future.