To investigate the influence of oxygen content in a physiological liquid environment on the corrosion behavior of biomedical zinc-based alloys, a simulated bodily fluid environment with varying dissolved oxygen was established in vitro using external oxygen supply equipment. The influence of dissolved oxygen concentration on the corrosion behavior of pure Zn and Zn-Cu alloys was studied with scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectrometry, and electrochemical analysis. Due to oxygen absorption corrosion, the increase in dissolved oxygen concentration increases the pH value of the solution and promotes the accumulation of corrosion product layer. Compared with the environment without additional oxygen supply, the corrosion rate of the sample under the continuous oxygen supply condition is increased by one order of magnitude. Because the Zn-Cu alloy has micro-galvanic corrosion, its corrosion rate is about 1.5 times that of pure zinc under different dissolved oxygen conditions.