PSA oxygen plant uses clean compressed air as raw material, zeolite molecular sieve as adsorbent, and uses PSA principle to obtain oxygen at room temperature. According to the difference of adsorption amount of oxygen and nitrogen on the surface of zeolite and the diffusion rate of oxygen and nitrogen in zeolite, the opening and closing of pneumatic valve is controlled by programmable controller to realize the process of pressure adsorption and pressure reduction desorption, complete the separation of oxygen and nitrogen, and obtain the oxygen of required purity.