The investigation on joining of SiC to SiC has been conducted for some years. It is essential that the mechanical and thermal properties of the joints should meet the requirements of engineering. In view of the fact that the ternary carbide Ti3SiC2 has shown unique mechanical and thermal properties, it is promising to join SiC to SiC using ternary carbide Ti3SiC2 as filler (welding compound), and this is the subject to deal with in this paper. The joining of SiC to SiC has been successfully realized by hot pressing reaction joining process using Ti3SiC2 powder as filler. The optimized technological parameters have been obtained by orthogonal experiments, under which the achieved weld strength is higher than that of the welding base material SiC ceramic. Ti3SiC2 is stable up to 1200oC in Ar atmosphere with an external pressure. At the joining temperatures of 1300～ 1600oC the main phases of the interface are Ti3SiC2, TiC and TiSi2. The mechanism of bonding at the interface is interdiffusion and chemical reaction.