Due to their excellent comprehensive properties, silicon carbide ceramics (SiC) are widely used in various fields. Wear-resistant and sealing component is one of the main applications of SiC ceramics. However, under dry friction conditions, such as high temperature, strong radiation and vacuum conditions, monothetic SiC ceramics have high friction coefficients and wear rates, and are prone to be destroyed due to wear, causing seal leakage. Therefore, there is an urgent need to develop SiC-based composites to improve the reliability of the equipment under complex working conditions. The dry friction coefficient of SiC can be effectively reduced by introducing a solid lubricant into the SiC matrix. Among many solid lubricants, graphite has good self-lubricating properties and possesses excellent properties, such as corrosion resistance, high temperature resistance, and radiation resistance. SiC-graphite self-lubricating composites prepared with graphite as the lubricant phase have great application and development potential especially in the field of nuclear power. At present, there are few reports on SiC-graphite composites. In this paper, dense SiC-graphite composites were prepared through process and carbon source optimization. In addition, the microstructure, mechanical properties, thermal properties, tribological properties of the composites were systematically studied. Firstly, SiC-graphite composites of different carbon source contents were prepared by using pressureless solid phase sintering method with mesocarbon microbeads (MCMBs) as the carbon source. By introducing 20wt% MCMBs, the dry friction coefficient of the composites was reduced from 0.63 for monothetic SiC to 0.25. The experimental results also pointed out that as the MCMBs content increases, the densification of the composite becomes more and more difficult. When the MCMBs content increased to 20wt%, the relative density of the composite was only 82.8%. Therefore, it’s necessary to carry out further research on the densification of the higher carbon content SiC-graphite composites from sintering process and carbon source. Based on the research of pressureless sintering, SiC-graphite composites were fabricated with MCMBs, flaky graphite and nano-carbon as carbon sources by hot-pressed sintering method. The densification research of hot pressing sintered SiC-graphite composite was carried out. It was found that, with MCMBs as carbon source, the material is the easiest to densify and has the best comprehensive performance. Using a two-step pressurization method, under the conditions of 2100℃, 50 MPa and1 h, dense SiC-30wt% graphite composite with excellent comprehensive properties was fabricated. The relative density of the material was as high as 98.6%, the flexural strength was 426 ± 17 MPa and the fracture toughness was 5.02 ± 0.18 MPa﹒m1/2, the dry friction coefficient μ≈0.22 and wear rate W≈2.44×10-7 mm3﹒N-1﹒m-1. The densification mechanism of the composite was studied, and it was found that the plastic deformation of MCMBs under pressure was the main reason for the high density of the material. The effects of the carbon source contents on the microstructure evolution, mechanical properties and thermal properties of the composite were studied. It was found that with same carbon content, the properties of the hot pressing sintered SiC-graphite composite were superior to those of pressureless sintered material, indicating that by using MCMBs as carbon source, through hot-pressed sintering can effectively promote densification and optimize properties of the SiC-graphite composite. The micromorphology and interface structure of the SiC-graphite composite containing 30wt% MCMBs were studied. It was found that the graphite layers formed by MCMBs graphitization grew perpendicular to the two-phase interface, forming a strong interfacial bond. The tribological properties and wear mechanism of the composite under different loads paired with different conterparts were studied. It was found that the tribological properties of the material are optimal when paired with self-mated counterparts. The study of the friction mechanism shows that the properties of the friction pair have a greater impact on the tribological properties and wear mechanism of the composite, but the impact of the applied load is relatively weak. In order to further explore a new method to densify SiC-graphite composite, spark plasma sintering (SPS) method was used to study the densification mechanism of SiC-graphite composites using flaky graphite and MCMBs as carbon sources. It was found that in the case of using flaky graphite as carbon source, it’s easier to achieve densification of SiC-graphite composite by SPS. It was also found that a small amount of flaky graphite can promote densification by increasing the discharge plasma density and driving force of sintering. Under the sintering conditions of 1900℃, 35 MPa and15 min, SiC-30wt%-graphite composite was fabricated, which has a relative density of 98.2% and dry friction coefficient μ≈0.16, wear rate W≈1.2×10-6 mm3﹒N-1﹒m-1. Based on the researches on the tribological properties of the material, the "wear and self-healing" mechanism of SiC-graphite composite was proposed.