In order to solve the conversion parameters of the laser tracker and the robot coordinate system quickly and accurately, a coordinate transformation method based on tool calibration and common point conversion is proposed. Firstly, the target ball was fixed on the robot end tool, the robot was taught to teach six different positions, and the center coordinates were measured by the laser tracker. Then, the position of the target ball in the robot coordinate system was calculated based on the distance constraint method; Finally, the least squares iteration based on Rodrigue matrix was adopted to coordinate transformation. The experimental results show that this method is simple and can avoid the influence of fitting error and improve the precision of coordinate transformation.