Abstract: An automatic design method of gas laser electrode has been developed based on the standard ACIS model format file. In the method, Ernst profiles are approximated by utilizing Inventor VBA program language and B-spline curve, and the 3D Ernst electrode entity model is obtained with the linear extension method. The object file can be exported to Ansys for 3D finite element analysis. The errors of the Ernst curves approximated with points of different density were compared, and the reason for the errors was elucidated. Denser sampling was adopted in the part of higher curvature to balance the curve precision and computing speed. The designed object was analyzed in Ansys program.