In order to improve the absolute positioning accuracy of a robot end-effector,a calibration method based on an improved particle swarm algorithm (IPSO) is proposed.Firstly,in order to avoid singularity in the model when two adjacent axes of the robot are parallel or close to parallel,the MDH model of series robot is founded.Secondly,according to the calibration features of robot geometric parameters,IPSO is used to optimize and calibrate the robot geometric parameters.The initial positions are generated based on Halton sequences and the particle velocity is modified by the constriction factor approach.The mathematical model of the objective function to calibrate robot geometric parameters based on IPSO is established,and detailed steps are provided for using IPSO to optimize geometric parameters.The results of the simulation and real calibration of the ER10L-C10 industrial robot show that the proposed method can quickly calibrate the geometric parameters of the robot,and the absolute positioning accuracy of the end-effector is greatly improved.The proposed algorithm is simple and robust,and is suitable to be popularized and applied in industry robot calibration.