Abstract: Sn-0.7Cu-0.5Ni brazing alloys with varying Ce content (0-0.30wt%) were prepared. The effects of trace rare earth element Ce on the solderability of the Sn-0.7Cu-0.5Ni brazing alloy on copper plate and mechanical properties of the joint were investigated through spreading test, tensile test, and SEM observation. The results show that the addition of 0.10wt% Ce significantly enhances the spreading of the brazing filler metal on the copper base material, achieving a maximum spreading rate of 81.2%. The tensile strength of the brazing filler metal is 44.2 MPa, and its elongation is 44.8%. The addition of Ce element refines the microstructure of the brazing filler metal, but excessive Ce forms brittle phases, which deteriorates the performance. An appropriate amount of Ce inhibits Cu atom diffusion, slows down the growth of the intermetallic compound layer, and enhances joint reliability. This study provides a basis for the development of high-performance rare earth brazing filler metals.