A experimentally study has been carried out to predict airflow rate, temperature field and velocity field for different chimney gap and heat flux. Results showed that, for veritical solar chimney,there is an optimum ratio of chimney width-to height to achieve a maximum airflow rate. The optimum ratio is about 1：2. Meanwhile,temperature and velocity field of solar chimney channel were analyzed. The air temperature and the velocity approaching to the surface of the heated wall are higher than that away from the surface of the heated wall.