To obtain tolerance limit of human upper extremity with arm restraint plate on eject seat to windblast, impact was applied to the upper extremity of 13 human corpses and 7 living monkeys by a spring driven impact device. Relationship between impact load, moment of elbow joints and arm injuries with arm restraint plate were studied. Relationship between biomechanical characteristic curve of human elbow joint and clinical injuries was obtained. The results indicated that tolerance limit of human upper arm is higher than forearm. Safety limit of human anterior arm to simulated aerodynamic load is 1.26 kN.