The invention discloses a mechanical optical gate of a superpower laser, comprising an optical gate box, a linear cylinder, a linear guide rail and an energy absorbing mechanism, wherein a semi-conductor red light generator is arranged on the optical gate box, an optical gate lens is arranged below the optical gate box, the optical gate lens is arranged under the center of the semi-conductor red light generator, and a red light reflecting mirror forming a 45-degree angle with a horizontal plane is arranged on the optical gate lens; the linear cylinder drives the optical gate lens to move along the linear guide rail; the energy absorbing mechanism is arranged below the optical gate lens and comprises an anti-reflection plate, an absorbing shell and an absorber core in the absorbing shell; and the anti-reflection plate is provided with a long-round open pore corresponding to the center of the semi-conductor red light generator. The mechanical optical gate overcomes the defects of an existing optical gate lens that the orientation is unstable, the movement displacement offset is large, the energy absorbing area is small and the efficiency of primary heat exchange is low; and the mechanical optical gate has the characteristics of high motion sensitivity, stable red light orientation and high energy absorbing efficiency.