Silicon carbide (SiC) ceramic has a broad application prospect in aerospace and nuclear power industries due to its advantages of high strength, high hardness and low density. However, the processing difficulty and low toughness of SiC hinder its application. To solve the problems above, SiCw/SiC composites containing different silicon carbide whiskers (SiCw) were prepared via binder jetting additive manufacturing and liquid silicon infiltration. The experimental results show that the flexural strength and fracture toughness of the composite can be 215.29 MPa and 3.25 MPa·m1/2 when SiCw contentis 7.5% (in volume fraction), and the hardness is 23.06 HV at 5% SiCw. However, the residual silicon phase content within the composite elevates, and the mechanical properties deteriorates when SiCw content further increases. The two carbonization processes to the green parts effectively reduce Si phase content and increase the flexural strength, fracture toughness, and hardness by 10.15%, 10.46%, and 10.58%, respectively. SiCw is added as a reinforcing and toughening agent for the composite ceramic via deflection cracking, pulling out and fracturing.