Abstract: In order to realize the path tracking and control of crawler tractor in the field under the complex environment, an automatic driving system was designed and the tracking algorithms of this system were studied. The automatic driving system contained MCU, double laser positioning system, speed control system, ignition/extinction control system, and hydraulic steering system, etc. To track and control the route of crawler tractor, fuzzy algorithm was used to compensate the deviation of the traveling process. Matlab/Simulate simulation and field experiment were made for testing the algorithm and results show that it can control the NF502 crawler tractor effectively within 100m，and it proved that the algorithm can track and control the crawler tractor’s route.