The turbulent diffusion coefficient is calculated with and without clouds in different weather systems at different time. The main results show that the turbulent coefficient of 3～4km height level distributes mainly between 20 and 70m²·s^-1 in clouds,and less than 30m²·s^-1 in cloud free areas. The turbulent coefficients in clouds generally increase with height,and little differences exist in every layer between winter and summer half years.