Abstract: On the basis of the method of direct least square ellipse fitting, an error control-based reconstruction method for ellipse leading edge and trailing edges of thin-walled blade is proposed. By setting the iterative fitting error threshold, the ellipse iterative fitting process can be controlled. When the average ellipse fitting error is equal to or less than the threshold, the iterative fitting process would be stopped, which can effectively prevent the non-edge points being involved in the fitting process. Furthermore, considering the requirement of the vertical smoothness of the blade, a parameter adjustment method was proposed, which could help to generate smooth surfaces of the blade edges. Finally, software modules based on the discussed methods were developed and verified based on real measurement data set.