In this study, the diffraction efficiency analysis of a rectangular groove grating and a triangular groove grating was performed using the vector diffraction theory. Accordingly, the diffraction efficiency of the triangular groove grating was found to be about one time higher than that of the rectangular groove grating. Based on a new five-axis ultra-precision single-point diamond lathe cutting technique, the diamond tool-head movement errors, the movement spacing standard deviation range and the machining deviation of grating line position are determined and the effect of tool-head wear on grating diffraction efficiency was also analyzed. On this basis, a convex blazed grating with curvature radius of 70 mm, groove density of 60 line/mm, and diameter of 52 mm was developed. And the peak relative diffraction efficiency is larger than 80% and the average relative diffraction efficiency is larger than 60% in the 1000-2500 nm spectral region. The actual hyperspectral data obtained during the flight shows that the shortwave infrared imaging spectrometer developed using the proposed convex grating meets the requirements of geological remote-sensing technology.