Spot positioning accuracy is an importantindicator for laser communication acquiring,tracking and positioning(APT) system,but the traditional spot positioning algorithm has some problems such as low positioning accuracy,poor anti-interference ability and poor real-time performance. In order to meet the requirement of high precision positioning of laser communication APT system,an improved laser spot center positioning method is proposed. The noise interference is reduced by improving the threshold segmentation to highten the positioning accuracy. The results show that compared with the traditional threshold segmentation method,the accuracy of the spot center is increased by more than 25%,so it is a feasible spot positioning algorithm.