The invention discloses a Mo-doped FeCo-based soft magnetic alloy, particularly a high-hardness soft magnetic alloy Fe44-xCo44Zr7B5Mox (wherein x is greater than 0 but less than 3), belonging to high-temperature soft magnetic alloy materials. The alloy is prepared by the powder metallurgy method with the coercivity thereof being 20Oe to 100Oe and the microhardness thereof being 200Hv0.05 to 350Hv0.05; by sintering the alloy at a proper temperature, the microhardness of the alloy can be greatly increased, and the alloy further has the advantages of higher hardness and good soft magnetic properties; by using the powder metallurgy method to prepare the alloy, the preparation process is simple, the forming ability is high and components taking various shapes and having both soft magnetic and mechanical properties can be prepared; and the mechanical properties of the prepared alloy can meet the performance requirements for electrical machinery materials in the field of aerospace.