Fertilization is the key link in fruit production. The quality of fertilization directly affects the nutrient absorption of fruit trees. Rational fertilization is an important measure to ensure the high yield, stable yield and increased yield of fruit trees. In China, orchard ditching fertilization mainly depends on manual work, which is of high intensity, low efficiency and low standard. Mechanized ditching fertilization is the key to solve this problem, and it is also the future development trend of orchard in China. Aiming at the problems of low fertilization efficiency and poor consistency of orchard ditching fertilizer machine, and the difficulty of mixed application of organic fertilizer and chemical fertilizer, a orchard double row ditching-fertilizer machine with automatic adjustment of ditching depth was designed. The working mode of double row ditching and fertilization was adopted, which can complete the ditching of fruit trees, the mixed application of organic fertilizer and chemical fertilizer, and the integrated operation of covering soil at one time. Through theoretical analysis and design of key components, such as ditching device, fertilization device and ditching depth automatic adjustment device, a core control system based on STM32F103 was built to realize the automatic adjustment of ditching depth. Performance and field tests showed that all working parts of the ditching-fertilizer machine operated stably, the ditching depth was highly consistent, and the stability coefficient of ditching depth was not less than 94.76%;the distribution of various fertilizer particles was uniform, the distribution stability coefficient of organic fertilizer was not less than 91.44%, the distribution stability coefficient of chemical fertilizer was not less than 92.09%, the distribution stability coefficient of mixed fertilizer was not less than 93.70%, and the evaluation index met the requirements of orchard production. The research results provided scientific reference for the design of orchard ditching-fertilizer machine, and it was of great significance to the mechanized production of fruit industry.