Abstract: The experimental model is established about the shunt for membrane separation nitrogen making device, and the air supply pipeline is of equal cross section and equal tuyere, to carry out the problem analysis and optimization for the shunting of air orifices of the shunt. The model is measured by the air distribution experiment, the results show that the air volume of each air orifice of the shunt is different, and the maximum deviation of its air distribution is 12%. Because the uneven distribution of the shunt has a negative effect on the membrane group, the experimental model of the shunt is optimized. The shunt is designed with an uneven distribution coefficient of 5%, which can be considered that the approximate equal air distribution of the shunt is achieved. On this basis, the diameter d of air orifice is the result of optimization design.