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To enable visual tracking of targets by intermeshing-rotor unmanned helicopters in the presence of unstable global positioning system (GPS) signals, a visual tracking control system for intermeshing-rotor unmanned helicopters is designed. Firstly, a vision module is designed to perform image processing on tracked targets, obtain the pixel coordinates of the center point of the tracked target using oriented FAST and rotated BRIEF (ORB) feature matching and rectangle detection. Thus, the actual position of the center point of the tracked target is solved by the camera model and the rotation matrix. Secondly, a tracking control module is designed with a serial proportional-integral-derivative (PID) plus feed-forward control structure. An open-square controller is used in the position control in order to limit the limit position and maximum acceleration, and an intermeshing-rotor attitude control mechanism is designed in the attitude control. Then, the simulation environment is built by the flight control ground station to simulate and verify the flight control system with the added vision module. The results show that the unmanned helicopter can track the desired position output from the vision module very well. Finally, the experimental validation is conducted under the conditions of the maximum flight speed of 1 m/s, the maximum attitude angle of about 8°, and the maximum error of 0.08 m between the position and the desired position. The experiment demonstrates that the proposed system can fulfill the visual tracking of the intermeshing-rotor unmanned helicopter for the target. [ABSTRACT FROM AUTHOR]