This separation process occurs in an adsorption tower and is advantageous in its low cost, low capacity, minimal maintenance requirements and user-friendly interface. The h2 purifying system removes oxygen from hydrogen via a catalyst to obtain high purity h2 after adsorption and drying through the dust filter. The system can remove oxygen down to levels of 1ppm. Through one step of purification, the purity of the hydrogen generated can reach between 99.999~99.9999% and the dew point can be lower than -70°c; through a second purification step, impurities can be , 0.8mpa H2 purity % >98-99.999% Dew point , -60°c Oxygen content , 1ppm