ing at the problem of how to obtain the relative position and posture of non-cooperative targets in space at close range for on-orbit service mission, a trinocular stereo vision measurement method is proposed. First, three large-field visible light cameras arranged in equilateral triangles are used to acquire images. Then, the proposed method is used to match the feature points. Second, the RANSAC method is used to calculate the pose parameters of the measured target in the world coordinate system. Finally, the static motion, position movement and attitude rotation of the non-cooperative satellite model are tested. Experimental results show that the relative position accuracy is better than 2.2 mm in the static state, and the relative angle measurement accuracy is better than 0.3°; when the model position moves, the absolute position accuracy is better than 3 mm; when the model posture rotates, the relative position accuracy is better than 5.6 mm, the relative angle measurement accuracy is better than 1.7°, indicating that the proposed method can improve the shortcomings of binocular stereo vision technology, such as measurement blind spots, mismatched feature points location and limited measurement field of view.