Abstract: Disk weight is assumed to be an objective function.Because a disk is configurated by straight lines and circular arcs,design variables constitute a point A（x1,x2）in two-dimensional space（see Fig.1）.Obviously,the longer the vertical boundary of a disk web is,the lighter its weight.According to this feature a direct search optimum method,longitudinal search-horizontal move method,is proposed for optimization of a disk with minimum weight and sufficient strength for centrifugal force,tensile stress from blades and non-uniform temperature field.While using this method,calculations need neither constraint gradient nor search direction,and the design variables are reduced to minimum.It is possible to obtain satisfactory results with less number of iteration.An example given for optimizing a disk with the computer program OPDISK has testified the advantages mentioned.The FEM for stress analysis is briefly discussed in this paper.By means of an 8-nodes transition isoparametric element,it is convenient to change meshes from coarse to fine one and divide into meshes automatically.