Abstract: The design and experiment of variable rate fertilizer applicator driven by home-made tractor were introduced in this paper. The applicator was guided by a GPS system. It can apply fertilizer based on the fertilizer prescription map. The mechanism of metering system for the applicator uses a flute wheel. The amount of fertilizer was determined by the rotation speed of flute wheel. The working process and structure of apllicator were also explained. The different kinds of fertilizer used for variable rate application were tested at four kinds of rotation flute speeds. The weight of fertiliizer every rotation was compared. It shows that the flute wheel can be used for metering fertilizer in variable rate applicator. The flute speed affects the precision of different kinds of fertilizer. The length of the flute needs to be extended when applying urine. And it needs to be decreased and increases its rotation speed when applying amonnia phosphate.