Abstract: The manipulator is an important device of anti-outburst and anti-impact drill rig, which is related to whether the drill rig can drill normally and truly realize unmanned operation. In order to ensure the rapid, accurate and stable operation of the drill rig manipulator, the trajectory planning optimization is particularly important. There are some problems in the existing trajectory planning of drill rig manipulator, such as higher order, prematurity of optimization algorithm and so on. In order to solve the above problems, a time optimal trajectory planning method of drill rig manipulator based on improved particle swarm optimization ( PSO) algorithm is proposed. Firstly, the 3D model of the drill rig manipulator is constructed by using the standard Denavit-Hartenberg ( D-H), and the workspace of the manipulator is obtained by Monte Carlo method, and four path points are selected as interpolation points from the workspace. Secondly, in order to make the manipulator reach the specified position quickly and smoothly, the trajectory of the manipulator is constructed by using 3-5-3 piecewise polynomial interpolation in the joint space. Finally, by the improved PSO algorithm, the constructed trajectory is optimized in the shortest time, and the optimal trajectory planning of the drill rig manipulator is obtained. The Matlab simulation results show that the time optimal trajectory planning method of the drill rig manipulator based on improved PSO algorithm can not only ensure the smooth operation of each joint of the drill rig manipulator, but also reduce the running time from 3.168 5 s to 2.385 4 s, reduce the overall running time by about 25% compared with that before optimization, and improve the efficiency of the manipulator.