The over goal of this study was to develop a laser scanner based automatic navigation system capable of guiding an autonomous mobile robot traveling in the orchard. An automatic navigation system, which consisted of a laser scanner, an inertial sensor, a DC PWM servo motor and a computer was developed and mounted on the mobile robot. A program based on quadratic curve was developed as the algorithm to planning navigation path. A controller based on fuzzy control was designed. The performance of the control system was tested in sinusoid condition at the travel speed of 0.54m/s, the maximum error was 0.40m and the mean error was 0.12m in the test. The test result demonstrated that the system could navigate the mobile robot to traverse a curve alleyway of a simulative orchard condition with a relatively good accuracy.