Abstract: Centroid location accuracy of stars directly affects the limits of star sensor attitude measurement accuracy, one centroid location error is selection of spot model of star image energy in the algorithm. Star sensor's optical system inevitably has aberration which leads to changing of spot distribution, therefore, it has a realistic significance to explore the effect of optical aberrations on centroid location error for engineering application. Compared with the Gauss function model, four kinds of optical aberration were studied such as defocus and distribution law of centroid location error under the influence of the optical aberration. The analytical expression of location error was calculated combining with the physical process of centroid location, and its numerical simulation was achieved. Experimental results show that the different aberration result in respective spot distribution, further, different centroid location error. And the centroid location error will decrease if the edge energy gets lower evenly at a slow speed according to controlling aberration well. The analysis of centroid location error will help to guide the latter systematic error compensation, and principle of controlling optical aberration will guide the optical system design of star sensor.