The invention discloses an actuator with a solenoid providing an axial permanent magnetic field. The actuator comprises a shell, an upper end cover, a lower end cover, the solenoid, a first magnetizer, a magnetostriction rod, a second magnetizer, a pre-pressing disc spring and an ejector rod. The solenoid forms an axial permanent magnetic field in an axial through hole, and the upper end cover andthe lower end cover are arranged at the two ends of the shell respectively to form an outer shell. The solenoid is arranged in the outer shell, the first magnetizer, the magnetostriction rod and thesecond magnetizer are installed in the axial through hole of the solenoid, the first magnetizer and the second magnetizer are located at the two ends of the magnetostriction rod, the pre-pressing discspring is installed between the upper end cover and the ejector rod, and an ejector rod through hole is formed in the upper end cover. One end of the ejector rod abuts against the second magnetizer,and the other end penetrates through the pre-pressing disc spring and extends out of the ejector rod through hole. On the basis of providing an excitation magnetic field, a constant permanent magneticfield is added, and thus, the actuator does not need to design a bias magnetic field, the space of the device is effectively saved, and the device is miniaturized.