The invention relates to the technical field of unmanned application, and discloses a water-bearing surface self-balancing grabbing device for an unmanned surface vehicle. The grabbing device comprises a gripper structure, a gripper controller and a self-balancing platform base; the self-balancing platform base is provided with a guiding rail mechanism; the guiding rail mechanism comprises a linear guiding rail, a stepping motor, a boss, a driven optical axis guiding rail and two optical axis guiding rails, the optical axis guiding rails and the driven optical axis guiding rail are located onthe two sides of the boss, the linear guiding rail is arranged between the top optical axis guiding rails, and the stepping motor is arranged at the upper end of the linear guiding rail and is electrically connected with the gripper controller; the self-balancing platform base comprises a pan-tilt, a driving controller, a brushless motor and attitude sensors, the attitude sensors are arranged at the top and bottom of the pan-tilt, and the driving controller is electrically connected with the brushless motor and the attitude sensors. The device has the advantages that compensation can be made on the surface tilting angle and the grabbing tilting angle of the unmanned surface vehicle, the problem of gripping object drift is effectively grabbed, the drifting tolerance degree is improved, andthe problem of unmanned surface shaking is solved to help better grabbing.