The invention relates to the technical field of external store separating wind tunnel tests, and especially relates to a monocular video measurement method for an external store separating locus wind tunnel test. The method overcomes the difficulties of marking point recognition and matching through the circulating coding of marking points when an external store wind tunnel model rotates. The method employs the principle of relative motion, respectively takes a wind tunnel test segment and the external store wind tunnel model as reference objects, solves the position and posture of a camera, further obtains the movement locus of the external store wind tunnel model, achieves the monocular video measurement of an external store separating locus, avoids a stereo matching difficulty of binocular video measurement, and is higher in flexibility and practicality.