A six-pole parallel gear pump was designed for the problems of poor pulsation quality,great mass and high cost of ordinary external meshing gear pump.The structure and working principle of the six-pole parallel gear pump were analyzed.The transient flow characteristics of the six-pole parallel gear pump were analyzed,and the flow curve function in a single cycle was derived.A mathematical model based on flow pulsation coefficient,flow pulsation frequency and pump volume was established,design variables were selected,constraints were determined,and the fmincon function in the MATLAB optimization toolbox was used to optimize the parameters of the objective function.Finally,the transient flow simulation and calculation of the characteristics of the gear pump were carried out for the six-pole parallel gear pump and ordinary external gear pump under the same theoretical flow rate and rated inlet and outlet pressure difference,and the results were compared and analyzed.The simulation results show that under the condition of reasonable structural design,the six-pole parallel gear pump plays an important role in reducing flow pulsation,reducing vibration,noise,weight and manufacturing cost,and improving working performance and service life.