Abstract: In order to investigate the effects of fertilizer briquette on biochemical characteristics of flue-cured tobacco planting soil and the development of flue-cured tobacco roots. Using strip and hole application of base fertilizer as controls, analyze the effects of conventional fertilizer briquette , potassium silicate replacing potassium sulfate to optimize fertilizer briquette and application sites and quantities of fertilizer briquette on soil biochemical characteristics and flue-cured tobacco root growth and development. The results showed that compared with strip and hole application of base fertilizer, using conventional fertilizer briquette for nutrient supply increased the activity of soil urease and sucrase, with an average increase of 51.1% and 32.7%, respectively. In addition, after 25 days of transplantation, the root activity increased by 28.8%, but the supply capacity of available phosphorus and available potassium was relatively low. Using potassium silicate instead of 25% potassium sulfate to optimize the formula of fertilizer briquette can effectively avoid excessive accumulation of nutrients, and the root vitality after 95 days of transplantation is 42.6% higher than that of conventional fertilizer briquette. Increasing the number of fertilization sites for fertilizer briquette can further improve the soil available potassium content, as well as the activity of sucrose enzymes and the number of microorganisms in the rhizosphere soil. It can also increase average diameter of flue-cured tobacco root by 18.4%. In summary, using potassium silicate instead of 25% potassium sulfate to optimize the fertilizer briquette formula and increasing the number of fertilization sites to 5 can significantly improve the biochemical characteristics of flue-cured tobacco planting soil, enhance its root vitality, optimize root morphology, and promote the formation of robust flue-cured tobacco roots.