Abstract: A tracer solution of Rhodamine-B mixed with water in 1 g/L concentration was sprayed in rice fields in place of pesticide. The deposit of spraying droplet in a certain area was surveyed with a fluorescence spectrophotometer. Results showed that when the rice plant was bedded in three layers of above 40 cm, 20-40 and 5-20 cm over the ground, the spraying droplet deposit was in direct proportion to the mass of dried rice plant. When the top layer mass of dried rice plant was 7. 325-147. 770 g, the mid layer mass was 8. 767-287.933 g, the bottom layer mass was 13. 630-571. 348 g, the proportional factors of droplet deposit to rice plant mass were 0. 187, 0. 066 and 0. 016 respectively. With the technology of DGPS, the maps of droplet deposit distribution both of total spraying and in different layers were plotted.