The invention discloses a high-precision large-caliber electric reflecting mirror frame based on an orthogonal axis, relates to an electric reflecting mirror frame, and aims to solve the problems that the process of guiding the transmission direction of a large-caliber laser beam is not precise enough and is not easily controlled, and collimated guide and near-field adjustment for the laser beam are poor in flexibility. A rack is connected with a pitching shaft frame through a rotation shaft, the pitching shaft frame is used for adjusting pitching angles relative to the rack, the pitching shaft frame and the rotation shaft are connected with a deflection shaft frame, the deflection shaft frame is used for adjusting deflection relative to the pitching shaft frame, a transverse positioning barrier strip is close to the inner side surface of a transition frame, an axial positioning barrier strip is close to the inner side surface of a second positioning frame, a mini-driver output end of a pitching shaft micro-actuator is connected with the pitching shaft frame through a pitching connection block, and a mini-driver output end of a deflection shaft micro-actuator is connected with the deflection shaft frame through a deflection connection block. The high-precision large-caliber electric reflecting mirror frame is used for a light beam guide system of an inertial confinement laser fusion device or other optical path adjustment systems needing large calibers.