This paper presents a simple method of solving plastic deformation of a rotating disk having nonuniform metal properties. A stress-strain surface, which is formed by stress-strain curves obtained from the tensile specimens cut at different radii of the disk in the tangential direction, is introduced. The distributions of plastic stresses and strains can be obtained by a simple multiplication with the use of a short table given in the paper and a stress-strain curve along the radius of the disk determined from the stress-strain surface. The rotating-speed parameter is simplified to a simple algebraic function of maximum octahedral shear strain of the disk, and a parameter determined directly from the stress-strain curve along the radius of the disk. A chart calculated from such relations is given. The relation between rotating speed and maximum strain determined from the chart are compared with the experimental data of disk test; results agree well.