The invention provides a holographic blazed grating manufacturing method. Through making a homogeneous grating on a substrate, taking the homogeneous grating as mask, and carrying out oblique ion beam etching, a needed blazed grating is obtained. Since time of positive ion beam etching can be controlled when making the homogeneous grating, a groove depth of the homogeneous grating is accurately controlled. In addition, after obtaining a photoresist raster through interferometric lithography, ashing technology can be increased further, a duty cycle of the photoresist raster is controlled, and a duty cycle of a needed homogeneous grating is controlled. According to the manufacturing method of the present invention, multi-parameter control of blazed grating manufacture is realized, and manufacture precision is raised.