There is a simulator for analyzing the plant-environment system in the National Institute for Environmental Studies. This simulator is a wind tunnel with air conditioner, solar simulator and control unit of soil environment. Profile of air temperature and humidity are controlled automatically in the simulator but that of wind velocity was not. Wind tunnels in other research fields have also been in a similar situation. We have therefore developed an automatic control system of wind velocity profiles in the simulator, and then examined the performance of the system and its application.