Abstract: In this paper, a prototype of a variable rate fertilizer applicator for precision agriculture was constructed. The applicator is based on DGPS satellite positioning principle. It combines GPS, GIS and DDG together to make fertilization decisions and to output the application rate of fertilization into an IC card. When the applicator works in the field, the position data received by GPS, which is equipped on the applicator, stimulates the fertilization decision command in the IC card. The command then controls the rotational velocity of the fertilizer shaft through a single chip computer to realize the variable rate fertilization. Experiment results in the field show that the fertilizer applicator is competent for variable rate fertilization for precision agriculture.