The invention discloses a laser efficient cleaning device for overlong linear light spots. The laser efficient cleaning device comprises a transfer frame, an optical system and a fiber laser, whereinone end of the transfer frame is connected with a working arm, the other end of the transfer frame is connected with the optical system, the fiber laser is arranged on the back end of the optical system, the optical system comprises a first cylindrical mirror, a second cylindrical mirror and a lens group, both the first cylindrical mirror and the second cylindrical mirror are in the shape of a crescent prism, light beams can be compressed in a cleaning feed direction and can be expanded in a vertical feed direction by the first cylindrical mirror and the second cylindrical mirror, the lens group is arranged between the fiber laser and the first cylindrical mirror, and the part of the center of the laser beams with high energy can be shaped by the lens group, so that high energy consistencyof the center and the edge is guaranteed, the laser efficient cleaning device is suitable for large complex members and has the advantages of high cleaning efficiency and good cleaning quality, and the problems of low laser cleaning efficiency and poor cleaning quality uniformity of existing large complex members are solved.