[Objectives] Aiming at the problem of point stabilization control of benthic AUV under unknown disturbances and uncertainties, a fixed-time backstepping controller based on fixed-time extended state observer is designed. [Methods] Firstly, according to the point stabilization tracking error model of AUV, a new fixed time extended state observer is proposed to estimate the unknown lumped disturbance and unmeasurable velocity, and the observation error can be converged to zero in a fixed time. Then, a fixed-time point stabilization controller is designed by using backstepping method based on the above observer. By adding a first-order filter, the inherent complexity explosion of the backstepping controller is solved, and the semi global fixed time uniform ultimate boundedness of the closed-loop system is proved by Lyapunov stability analysis. [Results] Finally, the feasibility and superiority of the proposed scheme are verified by simulation experiments. [Conclusions] The simulation results show that the proposed scheme can solve the point stabilization control problem of benthic AUV affected by unknown disturbances and uncertainties, and improve the convergence time of the control system.