In recent years, because solar simulator can accurately simulate the sunlight, a growing number of space experiments apply solar simulator to simulate temperature environment on the ground. A large solar simulator with 2 m- diameter effective beam was introduced, and the collimator was made up of 19 unit spherical mirrors. Common alignment methods of spherical mirror were analyzed, and on the basis of spherical center self-collimated method, an alignment method of segmented collimating mirror was given. Alignment process was explained in detail and effective aperture was 2 710 millimeters and radius was 13 280 millimeters. In addition, radiation characteristics test methods and devices of the large solar simulator were also introduced, under atmospheric environment and in vacuum cryogenic environment and in vacuum thermal test, which provided reference for the better use of solar simulator in engineering.