The application amount of chemical fertilizer in Linyi City has been in a downward trend in recent years, but the application intensity of chemical fertilizer has not reached the national and international standards. Based on the panel data of Linyi City from 2010 to 2019, the grey GM (1,1) model was used to predict the future trend of chemical fertilizer application intensity in Linyi City, the application of chemical fertilizer in Linyi City, and the years required to meet national and international standards were calculated.The elastic decoupling model was used to analyze the relationship between chemical fertilizer application and agricultural growth in Linyi City. The LMDI decomposition model is used to decompose the chemical fertilizer application in Linyi City into scale effect, structure effect, market effect and efficiency effect, calculate the contribution value of each effect, and put forward the driving mechanism of chemical fertilizer reduction in Linyi City, so as to provide theoretical guidance for chemical fertilizer reduction in Linyi City. The results show that the application intensity of chemical fertilizer in Linyi City will reach the national standard by 2027 and the international standard by 2030. The elastic decoupling coefficient of Linyi City has reached absolute decoupling in recent ten years, except for the expansionary connection from 2016 to 2018, and most counties and districts have been absolutely decoupled, indicating that the agricultural output value of Linyi City and its counties and districts has little relationship with the change of chemical fertilizer application in recent years. The main effects of fertilizer reduction in Linyi are market effect (negative effect) and efficiency effect (positive effect), while scale effect and structure effect have little impact on fertilizer reduction in Linyi. Therefore, we should unswervingly strive to improve the efficiency of chemical fertilizer, increase agricultural investment, farmers' fertilization training and improve the planting structure are necessary.