A experimental method is developed for elastoplastic stress analysis of a rotating disk by means of photoelastic coating and photoplasticity.The experimental results are obtained from elastoplastic strain measurements of a model disk and a compressor disk.The isochromatic fringe fields of rotating disks are recorded by two systems which are designed by authers and composed of derotator、strobe light、photoelectric detector and camera.Strips method and difference method are proposed to separate strains in the photoelastic coating.The elastoplastic stresses of the rotating disk are calculated from experimental data according to small deformation elastoplastic theory.This experimental method has the advantage over other methods in noncontact measurement of the whole field.