Abstract: In order to study the relationship between the droplet and drift, the characteristics and performance of sprays produced by agriculture flat-fan nozzles were measured with Phase Doppler Particle Analyzer(PDPA). Additionally the spatial distribution of droplet size and velocity were investigated, and the highly driftable area was ascertained. The results provide a reliable basis for the analysis of droplet deposition and drift. It is found that on sections below the nozzle, the droplet size distribution is like the inner surface of a rugby. The Median Volume Diameter(MVD) is the smallest at the centerline and increases with the distance from the centerline. But the distribution of vertical velocity is like a small hill, and declines toward the edge of the spray. The outer spatial region of the spray where the droplet density is low, and small droplets with little energy are easy to be vaporized because of the environmental factors, is the highly driftable region.