The utility model belongs to the technical field of mechanical test equipment, and discloses a universal rotary loading reliability test device for an electric spindle of a boring mill. The device comprises a main shaft mounting and fixing module, a lateral torque loading module, a universal rotary loading module and a detection module, the main shaft mounting and fixing module comprises an electric main shaft and a force bearing shaft; the force bearing shaft and the electric main shaft are fixedly connected with the broach mechanism through a universal matching conical surface; the lateral torque loading module comprises a torque applying part and a radial force compensation part; the torque applying part comprises a dynamometer; the radial force compensation part comprises a radial force compensation device; a rotary supporting body in the universal rotary loading module and the force bearing shaft are coaxially arranged in space; the detection module comprises a radial run-out detection device and an axial displacement detection device; the problem that existing related equipment can only adjust the loading direction statically is solved, and the function of continuously changing the loading force direction while dynamic force is applied to the electric spindle is achieved.