A set of variable-rate continuous spray equipment was developed by using the proportional regulating solenoid valve based on pulse-width modulation (PWM) technology. The effects of this variable-rate spray equipment on spray characteristics were studied. It was concluded that the flow regulating range of this set was wide. The flow regulating range for the flat-fan nozzle was about 7:1. When the spray flow-rate was reduced through decreasing the duty cycle, the degree of spray dispersion was changed significantly. The spray distribution concentrated toward the center obviously and the spray angle became smaller. But the effects of the flow control on spray droplet diameter were slight. The spray droplet size decreased slightly with the flow decreasing.