Using Cu-Ti+Mo composite filler, 2D C/SiC composite was brazed to GH783 nickel-based alloy under vacuum condition. The microstructure of the joint and the effect of Mo content on microstructure and properties of joints were investigated. The results show that the joint is composed of 4 regions: interface reaction layer, stress relief layer, soft metal layer and diffusion layer, without holes, cracks or other defects. The maximal flexural strength reaches 141 MPa with 15% (mass fraction) Mo particles in the joint, and the flexural strength of the joint declines when Mo content exceeds 15%. The Mo addition releases the residual stress of the joint, and inhibits excessive reaction between Ti and C/SiC, thus effectively improving the strength of the joint.