Abstract: Intelligent flexible farming platform is the basis of precision farming. Automatic guidance was one of the important technologies for intelligent farm machine. For studying the intelligent farm machine and its automatic guidance control, a field intelligent chassis for precision farming was developed. Two electric motors were used to drive the chassis by means of speed reducing mechanism and control unit. The navigation control system was developed based on the intelligent chassis using GPS and digital compass. The chassis could move along the fixed line, turn around and stop automatically. Test results indicated that the navigation error was less than 2 m when the intelligent chassis ran following the predefined route. The improved method was put forward based on the analysis of the test results. The chassis could be used as a working platform for precision fertilizing, spraying and so on.