The invention discloses an optical cooperative orbit determination method for a small celestial body surrounding detector, and belongs to the technical field of deep space detection. The method comprises the steps: taking the positions and speed vectors of two detectors as to-be-estimated state variables, and establishing an optical collaborative orbit determination state model under a small celestial body fixed connection coordinate system; imaging the observed detector through a camera of the observation detector to obtain pixel information of the observed detector in a phase plane, and establishing an observation model of optical collaborative orbit determination in combination with the known attitude of the observation detector; employing a nonlinear navigation filtering algorithm to carry out cooperative estimation on the positions and the speed vectors of the two detectors, and achieving the optical cooperative orbit determination of the small celestial body surrounding the detectors. The method comprises but is not limited to two detectors; when multiple detectors are arranged, relevant detection attributes are given to the detectors according to the actual small celestial body surrounding detector optical collaborative orbit determination requirement, and small celestial body surrounding detector optical collaborative orbit determination is achieved by observing opticalmeasurement between the detectors and the observed detector.