To solve the problems of low precision and large error of traditional navigation modes, a landing sign based on ArUco code is designed in combination with visual navigation.After processing the real-time images collected by the airborne camera, the UAV pose estimation model is established by using the mapping relationship between the world coordinate system and the pixel coordinate system.The estimated value of relative attitude between the UAV and the landing marker is obtained by solving the coordinates of the feature points.The error model is designed and fused to further improve positioning accuracy.Through the outdoor practical application experiment of UAV, it is proved that the designed landing sign and new recognition algorithm greatly improve the accuracy of UAV autonomous landing, which can be better applied to scenarios with high-precision landing requirements such as military UAVs.