Abstract: The attitude system of vertical take-off and landing (VTOL) multi-rotor unmanned aerial vehicle (UAV) is characterized by high nonlinear and strong coupling. And the external disturbance and internal uncertainty in the system will affect the flight quality of multi-rotor UAV. In order to improve the stability and robustness of the UAV attitude control, the attitude system of multi-rotor UAV coexisting with external disturbance and internal uncertainty is established, and an adaptive attitude control method based on the improved double closed-loop integral sliding mode is proposed in this paper. Through simulation verification, the proposed system can perform the attitude control task effectively and steadily, which possesses certain anti-interference ability. The method proposed in this paper can provide certain reference value for the development of UAV control technology.