The invention discloses a sprocket fatigue test tester and test method. The tester comprises a driving system and a braking system, wherein the driving system comprises an AC servo motor, an output shaft of the AC servo motor is connected with a planetary reducer input shaft, a planetary reducer output shaft is connected with one end of a driving shaft through a first shaft coupling, the other end of the driving shaft is connected with a driving sprocket three-jaw chuck, a driving sprocket is fixed on the driving sprocket three-jaw chuck, the braking system comprises a one-dimensional motion platform, the one-dimensional motion platform is provided with a magnetic powder brake, an output shaft of the magnetic powder brake is connected with one end of a torque sensor through a second shaft coupling, the other end of the torque sensor is connected with one end of a braking shaft through a third shaft coupling, the other end of the braking shaft is connected with a braking sprocket three-jaw chuck, and a braking sprocket is fixed on the braking sprocket three-jaw chuck. The tester is advantaged in that for certain work conditions, corresponding alternate loads are inputted to reflect actual sprocket fatigue performance.