CORC (cable on round core) has many advantages such as high current-carrying density and excellent mechanical properties. CORC conductor for nuclear fusion magnet could achieves tens of thousands amperes. However, the joint resistance, which influences the thermal stability of CORC conductor, is negligible. Besides, the joint needs to have a uniform current distribution for each parallel connected superconducting tapes. Thus, the development of a compact, low-contact-resistance joint is significant for the application of CORC. In this paper, 2 CORC cables manufactured with the same parameters, and the joint of the cables are manufactured by solder filling method. The critical current reaches 5000 A. An experiment was designed to evaluate the contact resistance between the single-layer tapes and the solder of one of the CORC cables, and the contact resistance was measured to be 8.65 nΩ. Melted joints, disassembled tapes were subjected to characterization tests for comparison with the original tapes, which showed that the critical current recession of the tapes after solder was small.