Abstract: In order to achieve high efficiency and universality in flow pulsation calculation of torsional rotorpump,taking the moving instantaneous diameter length of conjugate contour segment on end profile as a variable,the theoretical flow formula with integral term and the fitting flow formula without integral term were derived basedon the construction method of the high-end profile of torsional rotor and the construction principle of axial torsionalrotor,and an example of an arc torsional rotor was given. The results show that the flow fitting result is in goodagreement with the exact result. The fitting method is simple and convenient with high precision;the pulsation coef-ficient and the torsional lobe angle have an approximately negative linear correlation. The larger the torsional lobeangle,the smaller the flow rate pulsation coefficient,and the better the pulsation quality;the torsion lobe angle of 60° was the optimal value of non-pulsating rotor profile structure,and the theoretical flow rate of the torsional lobeis equal to the mean value of the theoretical flow rate of the straight lobe.