In view of the diverse and complex requirements faced in current industrial production,an N-type axis regulating mechanism suitable for diaphragm pump was designed by referring to the regulating mechanism in the transmission device of the existing plunger metering pump.The important parameters and correlative factors in the diaphragm pump operation were cleared,the relationship with the regulating mechanism in the power end was understood.The crank length was calculated through the parameters of the diaphragm pump,the mechanical model of the N-type axis was established,the stress was analyzed,the section stress of the crank under the combined action of bending and torsion was calculated,the optimal eccentric angle of the N-type axis was deduced,then other sizes were selected according to this.Finally,the preliminary scheme was designed according to the known size,and the structural size was further optimized by using the secondary development method of finite element software.The appropriate material was selected to obtain the final scheme.The calculation results show that the new N-type axis regulating mechanism service life and safety factor have been greatly improved,and the mechanism is more compact and the overall vibration is less,which makes the flow of diaphragm pump more stable and accurate.