The invention relates to fertilizing devices and particularly relates to a fertilizing device for highway plants. The fertilizing device for the highway plants, provided by the invention, is simple in fertilizing, convenient in operation and high in fertilizing speed. The fertilizing device for the highway plants, provided by the invention, comprises a trolley, a servomotor, a left bearing seat, a lead screw, a nut, a right bearing seat, a bracket, an air cylinder, a sprayer, a pull wire, a roller, a water inlet pipe, a mixing tank, a charging pipe, stirring vanes, a rotary rod, a rotating motor, a protective hood, an electrically-controlled valve and a hose, wherein the servomotor, the left bearing seat and the right bearing seat are sequentially arranged at the top of the trolley from left to right, the lead screw is arranged between the left bearing seat and the right bearing seat, the left end of the lead screw is connected with the servomotor, and the nut is arranged on the lead screw. According to the fertilizing device for the highway plants, the effects of being simple in fertilizing, convenient in operation and high in fertilizing speed are achieved, and the plants can be excellently fertilized by using the device.