Abstract: In order to satisfy the high precision measurement requirement of angular velocity of platform drift in a platform drift measurement system, an improved Gaussian fitting method of laser spot center positioning was proposed based on the Fourier series. By using this method, Gaussian fitting model was simplified and at the same time the precision of laser spot center positioning was relatively high. Experimental results show that center positioning accuracy of the improved Gaussian positioning algorithm is 0.01pixel, better than 0.1pixel of traditional centroid method and centroid method with threshold significantly. The improved algorithm in this paper has better algorithm stability.