Abstract: Low-density steel samples were prepared by spark plasma sintering, and the sintered samples were subjected to solution heat treatment and aging heat treatment. Through the comparative analysis of the density and microstructure the sintered samples before and after heat treatment, the effect of heat treatment on the microstructure and mechanical properties of sintered low-density steel was studied. The results show that the microstructure of sintered low-density steel is ferrite + austenite, the pores are enriched with C element and the C content in the pores after heat treatment is high; After heat treatment, the tensile strength increases from 403 MPa to 584 MPa and the microhardness increases from 518 HV to 541 HV. There is no significant difference in the friction coefficient of the sintered samples before and after heat treatment.