Abstract: In order to solve the problem of low mechanization rate of sandy soil amelioration and improve the mechanized laying efficiency of soil amelioration materials, this paper presents a precise and controllable solid material spraying scheme and designs a precise variable full-width material spraying device. Based on the analysis of the force and movement of the material spraying, the dynamic model of the material particle movement on the plate is established. Based on the discrete element method, a quadratic regression model between test factors and test indexes was established, and single factor analysis, variance analysis and objective parameter optimization were carried out. The results show that the order of the influence of each factor on the distribution variation coefficient is the adjusting board, the rotational speed of fertilizer wheel and the number of plates. The research results can provide reference for the design of machinery for sandy soil improvement and solid fertilization in agriculture.