Abstract: A novel subpixel location algorithm for elliptic center of circular targets image based on Zernike moment and curvature preserving is proposed.Firstly，pixel-level edges are detected and noises are filtered by multi-structure element multi-scale edge detection algorithm based on mathematical morphology.Secondly，a Zernike moment model for ellipse is developed and linked with curvature preserving to detect the subpixel edges.Finally，the subpixel elliptic center can be accurately obtained by fitting the edge points using least-squares fitting method.The experimental results indicate that the algorithm for circular targets center based on Zernike moment and curvature preserving has advantages such as faster computing speed and higher location accuracy，and it is very effective in high accuracy vision measurement.