Objective In order to optimize the aerodynamic performance of a small high-pressure axial flow fan we proposed to study the different load distributions of the inlet guide vane and dynamic vane to find the suitable distribution law for aerodynamic performance optimization. Methods According to the different load ratios of the inlet guide vane and dynamic vane distribution the corresponding inlet guide vane prewhirl angle and dynamic vane installation angle were designed and the fan model was established by using Pro-e 3D modeling software. Through numerical simulation ICEM was used for grid division and appropriate governing equations and boundary conditions were selected in Fluent solver for calculation. The aerodynamic characteristics pressure distribution velocity distribution turbulent kinetic energy distribution and internal flow field of different fan models were studied and analyzed. Results In the design of small high-pressure axial flow fans the inlet guide vane bears different loads due to negative deflection which has a great impact on the aerodynamic performance of the fan. When the airflow prewhirl angle of the inlet guide vane varied within the range of 30 ° ~ 50 ° near the design condition the smaller the negative prewhirl deflection angle of the inlet guide vane i. e. the smaller the design load ratio the higher the overall pressure coefficient of the fan. At the design operating point the difference in pressure coefficients of the five fan models could reach 9. 54% and the difference in full pressure efficiency of the five fan models was 2. 49% when the airflow prewhirl angle was greater than 30 ° i. e. the design load ratio ξ exceeded 32% the pressure coefficient of the high-load axial fan gradually decreased from 0. 332 to 0. 303 and the full pressure efficiency also showed a decreasing trend. Conclusion When the inlet guide vane prewhirl angle is controlled within 30 ° the pressure gradient in the middle and rear of the blade is small the velocity gradient in the circumferential direction is reduced the boundary layer separation at the trailing edge of the blade is improved the gas flow is stable the airflow distortion at the inlet of the rotor vane is reduced and the flow loss between the inlet guide vane and the rotor vane is effectively controlled.