Aiming at the pose measurement of soft aerial refueling cone sleeve, we use monocular vision theory to propose a pose calculation method of taper sleeve. Firstly, we establish the monocular vision model, and reconstruct the cone sleeve in three dimensions to obtain the coordinate values of three-dimensional key points and the real pose of the cone sleeve. Then, using 2D key point coordinates combined with 3D key point coordinates, we use EPnP and ICP to estimate the pose of the taper sleeve relative to the camera. The results show that the three-axis Euler angle error of the cone sleeve estimated by our method is within  ±10°, and the three-axis positioning error of the cone sleeve is within ±10 cm, which can achieve centimeter-level positioning accuracy with high accuracy and meet the relative navigation requirements of aerial refueling.