The invention discloses a reactor coolant pump water lubrication radial bearing test device and a test simulation method. The invention discloses a reactor coolant pump water lubrication radial bearing test device. An elastic pin coupler can regulate the shaft centering, bears a big instantaneous overload and performs buffer vibration absorption; a single-row deep-groove ball bearing can bear the axial force under an operation working condition and can guarantee the smooth operation of the shafting in the high speed working condition; electromagnetic induction heating can realize the application of different stage temperature loads on the periphery of the bearing; a pressure pump and a regulation valve in a circuit can perform regulation on the bearing cooling water quantity, pressure and temperature; a water tank heater and a cooler regulate the bearing to inject the cooling water temperature; and the test device has the same working condition with the bearing in the reactor coolant pump. The invention is simple in structure, strong in adaptability, wide in application range and is applicable to the performance test of different stage water lubrication radial bearing.