In order to conduct the experimental study on the mechanism of drying agricultura1 materials, an industrial PC-based unit of experiment apparatus was developed. Hot air temperature, humidity and flow rate can be monitored and adjusted using this system. Through the adjustment and contro1 of temperature, humidity and flow rate of dry medium air, basis and conditions can be provided for simulating different drying conditions for different kinds of drying materials, and weight and temperature of materials can be online measured, so as to confirm the optimum drying technology and the heat and mass transfer characteristics.