Abstract: As for the craters on the surface of planets can be used to autonomous navigation and obstacle recognition,the craters detection algorithm based on multiscale edge extraction is proposed. In this algorithm,different scale craters are detected through the Gaussian pyramid. For the different scales of crater images,firstly,using edge drawing parameter free(EDPF)to get edge segment of crater,and connecting critical edge pixels into line segment for representing the edge segment;then joining the line segments with the same turn direction into circular arcs,and fitting circular arcs with similar radius and center into candidate circles or ellipse,finally validating candidate circles and ellipses through calculating the number of false alarm(NFA). Especially,the algorithm can be used to detect craters accurately with high detection rate,and has good performances in images with many craters.