Accurate measurement of rocket height is one of the important preconditions to complete the rocket recovery task. In o-rder to realize the real-time measurement of rocket height， the rocket recovery height measurement technology was studied based on monocular vision. Firstly， in view of the smoke scene in the process of rocket recovery， the transmission function was improved bas-ed on the He Kai light-dark channel de-fogging algorithm in combination with Retinex theory， so as to improve the adaptability o-f the de-fogging algorithm to different fog environments. Secondly， according to the characteristics of target in rocket recovery， an algorithm suitable for target feature extraction was proposed， and the feasibility and reliability of the algorithm were verified by e-xperiments. According to geometric characteristics of the rocket and the ground target， the mathematical model is built， and feasib-ility of the altitude algorithm is analyzed quantitatively by designing experiments. Finally， the influence of different defogging alg-orithms on the height measurement results under different fog concentrations is quantitatively analyzed. The simulation and exper-imental results show that the accuracy of rocket height calculated by the proposed method is within 0.5 m， which can meet the de-mand of height measurement in rocket recovery.