Abstract: Under the weight of more than 100 kg, the automatic glass window composes the nature ventilation system of the special-shaped conservatory in Beijing Botanical Garden. That were used in the conservatory since 2000, a lot of problems of the automatic windows had occurred in succession, more than 50% windows were out of work in 2003. In order to maintain the environment control of the nature ventilation system, based on the principle of servo control and application of photoelectric sensor to opener, the authors developed a new synchronous control system for the automatic glass windows. The synchronous controller adjusts the working state of the two openers which send the feedback signals to the controller, so the two openers work synchronously at all time. The moving error between the two openers of one window is not more than 1 mm. The synchronous control system was used for the desert zone, the result of the feasibility test was satisfactory. The synchronous control system is a practicable method to solve the automatic window problems of the conservatory.