Abstract: This paper discusses the experimental data which collected in a turbulent diffusion experiments conducted in the boundary layer over Beijing by using the technique of radar-chaff.The carbon wire(diameter:8 μ; resistivity:1.7×10-3 ohm.cm) was used as the meterial of chaff; and the echo signal was detected by the weather-radar of modal 711(3cm) and model 713(5cm).Theoritical and technical problems concerned with the Radar-chaff technique have been analysed.It is evident that the method has advantages of simplicity and man-power and material saving.The behavior of turbulent diffusion could be measured within the range of 10 km.