In a hybrid loading test, actuators are usually pin connected to a specimen at one end and a loading frame at the other end. Under this condition, if the structure is loaded, a secondary force is induced by actuators due to P-Δ action of actuators. This paper presents a numerical simulation and a bench mark test to show the importance of modification of the P-Δ action in a hybrid loading test. It was found that if the P-Δ action of actuators is disregarded, a larger residual drift is likely to be developed. The bench mark tests provide responses which are quite close to the responses predicted by the fiber model. This shows the effectiveness of the modification.