The invention relates to an optical fiber fixing device coupled with a high-power semiconductor laser. All substrates, fast axis collimating lenses FAC, slow axis collimating lenses SAC and reflectors are fixedly arranged on different steps of a base respectively, each laser diode is fixedly arranged on one substrate, multiple laser diodes generate multiple light beams in different altitudes, the multiple light beams in different altitudes are subjected to respective fast axis collimating lenses FAC and slow axis collimating lenses SAC to generate parallel light beams in different altitudes; the parallel light beams are subjected to respective reflectors to reach the collimating lenses, and the multiple parallel light beams in different altitudes focus on an optical fiber by passing the collimating lenses; a boss is designed at the optical fiber fixing position of the base, the boss is integrated with the base, a V-shaped slot is designed on the upper surface of the boss and along the direction of the parallel light beams focusing on the collimating lenses, and the optical fiber is arranged in the V-shaped slot and is filled with glass solder and fixed. With the adoption of the optical fiber fixing mode, light in the cladding is separated, and the optical fiber is protected against being burned. Heat in the glass solder is dissipated out through the base.