In order to solve the cooperative pose of small-scale space robots by means of visual measurement, a cooperative pose measurement system based on monocular vision is designed. Firstly, a cooperative target with wide range of functions, high precision and strong robustness is designed for complex space working conditions. Secondly, one-pixel-width edge extraction algorithm is designed by image gradient method, and target identification is done with center matching and other constraints. Thirdly, the relationships between distance of feature points and precision of pose measurement are derived, and the extraction strategy of feature points based on partition processing is designed to realize the extraction and number of feature points in complex conditions, expand the working distance and improve the precision of pose measurement. The experimental results show that the processing speed is about 84.3 ms/frame in Matlab for the image of 640 pixel×480 pixel. Pose measurement errors are less than 5 mm and 1° within the range of 2.2 m. This system meets the cooperative task need of small-scale space robots.