Abstract: It was first to study the droplet deposition and penetrability in tree crown by the wind tunnel.The test results showed:(1)The lower the wind speed,the shorter the penetrating distance of the droplet.The longer the distance in the tree crown,the lighter the weight of the droplet deposition.(2)As the angle of leaf against the wind was increasing from 0° to 90°,the droplet deposition in the outside layers of testing tree crown was also increasing,but the reverse was that it was decreasing in the inside layers of tree crown.The study was quantitatively described the droplet penetrability and drift under the definite natural circumstances.It supplies a scientific basis for accurately using pesticides,enhancing the result of the prevention and control,and decreasing the environmental pollution.