The present disclosure discloses a hundred-kilowatts-level monolithic fiber laser based on auxiliary lasers and hybrid cladding pumping scheme. Multi-wavelength auxiliary lasers and a signal laser are simultaneously coupled into a core of a gain fiber, and the gain fiber provides gains for the auxiliary lasers and the signal laser under multi-wavelength cladding pumping. The multi-wavelength auxiliary lasers and the signal laser are sequentially amplified under the action of gain competition, and the amplification of signal laser is suppressed at a front segment of the gain fiber, while the signal laser is effectively amplified at a rear segment of the gain fiber after the multi-wavelength auxiliary lasers are reabsorbed; quantum defects generated are reduced, and uniformly distributed thermal loads will be achieved, and the bearing capacity of laser power is improved, thereby further achieving inhibition on the transverse mode instability effect.