The convex grating is one of the key elements in hyperspectral imaging spectrometers. In this paper the diffraction characteristics of the convex blazed grating is investigated by using rigor ous coupled-wave theory, which indicates that within the wavelength from 0.4 m to 0.8 m, the plus first-order diffraction efficiency can be over 35% through controlling the blaze angle of blazed grating. The convex blazed grating w ith the period of 5  m in the center, the blaze angle about 4.3 degree, and the ruled area – a convex substrate with its radius 72mm and aperture 35mm has been fabricated by holographic- scan ion beam etching. Experimental measurements show that the plus first-order diffraction efficiency is more than 35%, within the wavelength from 0.4  m to 0.8  m. Keywords: Diffraction gratings; convex blazed grating; holographic lithography; scan ion beam etching; diffraction efficiency