The invention provides a multi-point pneumatic optimization design method for an axial flow fan, and relates to the technical field of axial flow fans. According to the invention, all sample elementsin the sample space are obtained through mapping from the parameter space to the sample space; The method aims at the same sample element in a sample space. according to the peak efficiency point boundary condition and the near stall point boundary condition of the prototype fan, the flow field of the sample element is solved to obtain the heat insulation efficiency of the peak efficiency point and the near stall point; After the adiabatic efficiency of all sample element optimization points is obtained, an adiabatic efficiency combination model is constructed so as to facilitate subsequent optimization work to obtain an optimal axial flow fan design scheme. According to the optimized scheme, the aerodynamic performance of two optimization points, namely the peak efficiency point and the near stall point, is obviously improved; Compared with a prototype scheme, the non-optimized point aerodynamic performance is also obviously improved, the stall flow is obviously reduced, and the blocking flow is obviously increased, namely, under the all-working-condition condition, the aerodynamic performance of the fan rotor is improved, and the stable working range is effectively expanded.