The invention discloses a high-precision and low-signal-to-noise-ratio elliptic star spot subdivision location method, and relates to the field of astronomy measurement and navigation, in order to solve problems of a spacecraft in high-precision star measurement under influence of high target magnitude, image motion and aberration of an optical system. According to the method disclosed by the invention, initial value of a Gaussian weight function is set, centroid is calculated through a weighted centroid method, position of the centroid is taken as central position of next frame of weight function, combination of a light intensity secondary moment is used as Gaussian width of the weight function, and the process is iterated through an iterative algorithm; as the weight function is closer to a light intensity function, subdivision location precision is higher; meanwhile, by changing the weight function in a self-adaptive manner, a signal-to-noise ratio of image is improved, and Gaussian width is calculated respectively on x and y directions, thus solving problems on high-precision subdivision location of high-magnitude and low-signal-to-noise-ratio spot and elliptic spot. The method disclosed by the invention has the advantages of high precision and capacity of resisting disturbance, and is applicable to subdivision location of low-signal-to-noise-ratio and elliptic spot.