A new technique for shape measurement of reflector was presented. This technique is based on incoherent imaging and phase-shift. COD camera was used to record images of sinusoid fringe pattern, which is generated by computer, displayed on computer monitor and reflected respectively by two objects named as reflector tested and reference mirror. The phase distortion caused by reflector tested can be worked out after measuring phase distribution of two objects by phase shift. The relations between the distortion and the gradients of the shape of reflector tested were derived. By figuring out the gradients, the shape tested can be restructured. This setup also leads a possibility of accurate phase shift and convenience to adjust period and direction of fringe pattern. The stimulation and experiment prove this possibility. Compared with other interference measurements, the method is cheaper,simpler and more flexible. Particularly it may do well in measuring the shape of aspheric reflector and sharp variant reflector.