In this paper, we proposed a high-precision centroid location algorithm based on cubic spline fitting and interpolation combining the advantages of centroid algorithms and surface fitting algorithms. Besides, the principle behind its double error suppression was given. The simulation showed that the location error of the proposed algorithm at different SNRs was significantly smaller than that of traditional centroid algorithms. When the SNR was 20 dB, the root-mean-square error of the proposed algorithm was only 0.003 pixel. Furthermore, the star images from real instruments verified the effectiveness of this algorithm once again. In summary, this algorithm can effectively suppress the location error and has strong noise resistance, which can be widely applied without requiring specific star models.