Laser spot center positioning is a key technology in optical detection.It is widely used in optical communication ATP systems,optical path auto-collimation control systems,and optical non-contact displacement angle measurement systems.Aiming at the problem that traditional charge-coupled device (CCD) detection methods cannot accurately locate non-uniform and non-ideal circular laser spots,a new method for detecting the center of a rotating laser spot based on a position sensitive detector (PSD) is proposed.This method is based on the working principle that PSD can continuously detect the position of the center of gravity of the light spot on the photosensitive surface.A laser experimental device with a fixed axis rotation and a controllable angle is designed.After processing by Kasa algorithm,the center position of the light spot is obtained.Compared with CCD,no image processing is required.In the experiment,a PSD spot center detection system was built,and the rotating laser spot mode was analyzed.The results show that the laser spot center positioning model has a linearity of -1.036 and a position resolution of 0.1μm,and accurately locates the movement track of the center of the spot.This method provides a new idea for real-time high-precision positioning of non-uniform light spots.