Zn alloys are deemed to be desired body implant materials because of their moderate degradation rate. In this paper, the microstructural evolution, mechanical performances, and degradability of Zn-2Cu alloy prepared by ultrasonic melt treatment (UMT) with different ultrasonic powers (0W, 300W, 600W, and 900W) were systematically studied. Under the condition of UMT, the coarse α-Zn grains of Zn-2Cu alloy were refined into fine equiaxed grains and the mean size was significantly decreased from 133.4 μm to 65.3 μm when the ultrasound power was enhanced. The precipitating CuZn5 phase was significantly refined from the coarse block into the spherical shape. Moreover, the fraction of the CuZn5 precipitates of the Zn-2Cu alloy was greatly reduced with the increase of ultrasonic power. Tensile tests showed that the ultimate tensile strength (UTS), yield strength (YS), and elongation (El) of Zn-2Cu alloy were remarkably enhanced to 203MPa, 167MPa, and 8.14%, respectively, when the Zn-2Cu alloy melting was treated by 600W power. It was found by electrochemical polarization test that the degradation rate of Zn-2Cu alloy treated by UMT with 0W, 300W, 600W, and 900W power in Hank’s solution was gradually decreased to 1.6312mm/a, 1.3206mm/a, 1.0992mm/a, and 1.2832mm/a, respectively. In addition, after the Zn-2Cu alloys were immersed in Hank’s solution for 30 days, the degradation rate of samples was summarized as 0W alloy (0.472mm/a) > 300W alloy (0.436mm/a) > 900W alloy (0.412mm/a) > 600W alloy (0.398mm/a). The studies verified that the UMT was a very valuable technology for preparing Zn-2Cu alloy, which can meet the requirement of mechanical properties and degradable rate as a promising implant material.