The invention discloses a pressing, bending and twisting composite stress test loading device, which comprises a base, a top beam, a reaction wall, a vertical pressure applying piece for applying vertical downward pressure to the top beam, and a horizontal thrust applying piece for applying horizontal force to the top beam, the top beam is arranged above the base, and the pressure applying piece is arranged above the top beam; one end of the horizontal thrust applying piece is hinged to the reaction wall, and the other end of the horizontal thrust applying piece is hinged to the top beam; thehorizontal thrust applying piece can extend and retract in the horizontal direction; the horizontal thrust applying piece and the vertical pressure applying piece are arranged at the two ends of the top beam respectively. According to the invention, the connection position of the horizontal thrust applying piece and the top beam is adjusted; or the connecting rod is used for replacing a horizontalthrust applying piece, loading of load coupling or arbitrary change of a single load of the test piece under the condition of composite stress of pressing, bending and twisting is achieved, the device has the advantages of being flexible in loading, easy to assemble, adjustable and high in applicability and practicability, and all components are detachable and convenient to transport and store.