Abstract: In view of the problems of high labor intensity of fertilization and spraying, low work efficiency, and low utilization rate of fertilizer and chemical liquid in hilly and mountainous areas, a vehicle-mounted fertilizer and spraying integrated machine was researched and designed. The machine structure and working principle of the machine were described, the key components of fertilization and spraying were designed, and the movement characteristics of fertilizer particles and the movement principle of the spray rod mechanism were analyzed. The machine sets the amount of fertilizer and realizes uniform fertilization through the fertilization amount adjustment mechanism and the fertilizing plate; the spraying volume was adjusted and the three spraying modes of vertical, inclined and ground spraying were adjusted by PWM（pulse width modulation） technology and the two-way multi-directional spray bar mechanism.The utilization rate of the medicine liquid was improved by the arbitrary switching of the medicine mode. The test results showed that the average fertilization amount under different fertilization openings was 16.56～540.76 g/min. When the opening of the fertilizer opening was 60%, the coefficient of variation of fertilization uniformity（C_v=9.01%） was the smallest and the fertilization performance is the best. During the spraying operation, the spraying volume range under different PWM duty ratios was 74.94～345.41 ml/min. When the PWM duty cycle was increased to 100%, the coefficient of variation of spray volume（C_v=2.54%） was the lowest and the spray performance was the best. At the same time, the control model of fertilization and spraying amount was established through experiments. The research results can provide technical and theoretical support for the design and development of fertilizer and spraying machinery in hilly and mountainous areas.