Abstract: The expanded perlite/desulphurized gypsum composite material was prepared with desulphurized gypsum and expanded perlite as the main raw materials. The single factor test method was used to study the effects of the material preparation method, the number of vibrations of the specimen, the amount of expanded perlite on their performance, and the optimal preparation method was determined. The results show that the desulfurized gypsum and citric acid are mixed and stirred well first, then the expanded perlite is added to stir, and finally the water is added and stirred to form the specimen directly. When the content of expanded perlite is 2.0%, the absolute dry flexural strength, absolute dry compressive strength, saturated water flexural strength and saturated water compressive strength of the composite materials are respectively 3.83 MPa, 8.92 MPa, 1.66 MPa and 4.26 MPa, the dry apparent density is 1.166 g/cm³, which met the requirements of the specification.