Abstract: Different contents of Mn element were added to CuZnNi alloy brazing filler. The effect of Mn element on liquidus temperature, wettability, and mechanical properties of brazing filler and joint was studied. The results show that liquidus temperature of brazing filler decreased gradually with increase of Mn content and liquidus temperature of brazing filler dropped 54℃ when mass fraction of Mn was 4.5%. Spreading area of brazing filler increased gradually with increase of Mn content and reached 298 mm² when mass fraction of Mn was 4.5%. The tensile strength of CuZnNi increased and elongation increased first and then decreased with increase of Mn content. The shear strength of brazed joints increased gradually with the increase of Mn content and the shear strength was 221.2 MPa while mass fraction of Mn was 4.5% which was increased by 16.1% compared with that of base brazing filler.