For small multi-rotor drones,there are vibrations caused by wind disturbances and motor vibrations during flight,which may increase the noise of sensors and lead to unstable flight.There is also the problem of complex adjustment of parameters due to uncertain structure and large external disturbances.To solve these problems,an improved Active Disturbance Rejection Control (ADRC) controller is proposed.The improved controller can greatly reduce the angular acceleration intermediate frequency noise based on the traditional frequency domain filter,compensate for the sensor and filter delay,and quickly track large disturbances.In addition,a tansig error feedback function is introduced to adjust the parameters of the observer.The improved controller only needs to adjust one parameter in most application scenarios by improving the traditional Extended State Observer (ESO),and can limit the expected angular velocity and angular acceleration.Simulation experiments prove that this algorithm can greatly reduce the impact of aircraft vibration and noise,and compensate for the phase lag of control data.The strong applicability of the algorithm has been verified through experiments on dozens of multi-rotor aircrafts of different sizes and configurations.