The invention discloses a method for determining a boundary layer edge position according to a flow field numerical value calculation result. A give flow field is respectively subjected to non-viscous calculation and viscous calculation, and a non-viscous calculation result is taken as a mainstream and is compared with speed distribution in a viscous calculation result so as to determine a boundary layer edge according to the definition of the boundary layer. The method for determining the boundary layer edge position according to the flow field numerical value calculation result can precisely determine the boundary layer edge without manually assigning mainstream speed.