The utility model relates to the technical field of water cup supports, and particularly discloses an automatic locking water cup support which comprises a water cup main frame, an installation adapter plate, a spring, a fixed arm and a movable plate, the installation adapter plate is installed on the water cup main frame, the water cup main frame is rotationally connected with the fixed arm through the spring, and the movable plate is installed on the installation adapter plate. The end part of the fixed arm is rotationally connected with the movable plate, and the water cup main frame and the movable plate are arranged in parallel. The water cup is fixed on the water cup main frame through mutual cooperation of the spring, the fixed arm and the movable plate, so that the water cup fixing frame is stable and attractive, the phenomenon that the water cup falls off due to vibration can be avoided, and the water cup fixing frame is more convenient to use.