The invention discloses a fatigue testing machine of a ball socket bearing of a main rotor of a helicopter. The fatigue testing machine is characterized in that a first rolling guide (26) and a secondrolling guide (29) are fixedly connected to a central upright post (16); a first supporting sleeve(25) is fixedly connected on the first rolling guide (26); a second supporting sleeve (30) is fixedlyconnected to the second rolling guide (29); both the first supporting sleeve (25) and the second supporting sleeve (30) support a main shaft of a rotor wing (3); an inner hole of an inner ring (24) of the ball socket bearing of an auto bank unit of a main rotor is matched with an outer cylindrical surface of the main shaft of the rotor wing(3); the inner ring (24) of the ball socket bearing of the auto bank unit of the main rotor is sheathed with an outer ring thereof to form a spherical pair. The invention can accurately simulate the real working conditions of the ball socket bearing of theauto bank unit of the main rotor, such as the temperature, the load, and the like, and accurately simulate the real movements of the ball socket bearing of the auto bank unit of the main rotor, such as the speed, the acceleration and the like. The invention has the advantages of compact structure, beautiful appearance and convenient operation and maintenance.