Drones are widely used in multiple industries due to their flexibility and mobility. However, sensor failure, as a key issue affecting its flight safety and control accuracy, requires efficient adaptive control methods to ensure system stability. This paper aims at the flight control problem of unmanned aerial vehicles (UAVs) in sensor failure scenarios and proposes a control strategy that integrates fault estimation and adaptive adjustment. By constructing a sliding mode observer and an adaptive controller, the flight stability and trajectory tracking accuracy under the fault state are achieved. This paper system model for unmanned aerial vehicle dynamics and kinematics analysis and fault diagnosis for narrative. Then, the sensor faults were estimated by using the sliding mode observer method and the effect was demonstrated on Matlab. Finally, the adaptive control system is designed based on sensor fault estimation, and the stability and effectiveness of adaptive flight control are verified on Matlab.