Abstract: Paths represented by discrete points are not suitable for agricultural machinery navigation path tracking directly for they are usually not smooth enough and have uneven distribution as well as discontinuous heading angle．A local path smoothing algorithm based on quintic parametric polynomial curve was proposed．Firstly, target reference point on path point list was calculated using real-time coordinates of agricultural machinery and smoothing section was required by expansion．Approximate arc lengths between each point and starting point within sequence were calculated and used as initial independent variables for polynomial curve．Polynomial parameters were calculated by the least squares method, and independent variables corresponding to each path point in smoothing section were optimized iteratively using Newton algorithm．Quintic polynomial curve was generated by repeating iteration process mentioned above．Three path sections were selected for path smoothing test and analysis．Results showed that the maximum absolute average error between smoothed curve and initial trajectory points was ≤0.0946 cm and the maximum absolute extreme error was ≤ 8.35 cm, indicating that algorithm could effectively smooth local discrete path with high precision．