Objective: Analyzed the influencing factors of the internal flow field pulsation characteristics of the new double circular arc gear pump, and adopt reasonable parameters to improve the output efficiency of the gear pump. Methods: The two-dimensional flow field simulation model of the gear pump was established, and the computational fluid dynamics software Fluent was used for simulation analysis to study the influence of different tip clearance, different gear eccentricity, load and speed on the instantaneous flow, flow pulsation and flow field characteristics of the oil outlet of the gear pump. Results: As the tooth tip clearance increased, the outlet flow rate of the gear pump gradually decreased. When the tooth tip clearance was 0.09 mm, the minimum pulsation coefficient of the outlet flow rate was 0.135, which was the optimal tooth tip clearance for the gear pump under this structural parameter. Due to the influence of load pressure and rotational speed, the central axis of the gear pump deviates. As the eccentricity of the central axis of the gear pump rotor increased, the outlet flow rate of the gear pump gradually increased. When the eccentricity was 0.05 mm, the outlet flow rate of the gear pump increased by 5.09% compared to without central deviation, improving the flow output. Conclusion: The main influencing factors on the flow characteristics of gear pumps are rotor speed and tooth tip clearance, and the influence of center deviation is relatively small.