The invention discloses an electric fatigue tester. The electric fatigue tester is used for fatigue tests and comprises a base; an electric cylinder mounting rack and a counter-force rack matched with the electric cylinder mounting rack in position are fixedly mounted on the base; a servo electric cylinder and a left clamp are fixedly mounted on the electric cylinder mounting rack and the counter-force rack, respectively; a displacement sensor is built in the servo electric cylinder; a force sensor and a right clamp are orderly mounted on the end portion of the electric piston rod of the servo electric cylinder; a receiving space for holding a tested product is formed between the left clamp and the right clamp; for improvement, a lateral force prevention mechanism is further arranged on the base and used for preventing the center shaft of the tested product from shifting. The electric fatigue tester has the advantages of simple structure, low production cost, no oil pollution, low noise and the like that an existing product do not have.