In order to make full use of 3-D spatial information in continuous visual images and solve the positioning problem of unmanned aerial vehicles(UAV) during autonomous landing, based on the principle of dense 3-D point cloud method and optical flow method, a localization method based on the image space of the same object at different time was proposed. By means of theoretical calculation and graphic annotation, and calculating the movement of a single pixel and the whole image, the deformations and quantities of continuous frame images were decomposed into spatial relative motion information of UAV and reference objects. Combining with the known motion parameters of the reference object, the position and attitude information of UAV was calculated. The spatial positioning method of UAV based on optical vision image was completed. This study provides a reference for the vision system to independently realize spatial positioning in the process of UAV landing and recovery.