The purple soil distribution area has concentrated rainfall and serious soil nutrient leaching，resulting in the decline of soil fertility，insufficient nutrient supply in the root zone，and poor root development.Improving the supply intensity of soil nutrients is conducive to optimizing the spatial distribution pattern of roots and promoting root growth.The raw fertilizer and organic material were mixed well and pressed into brick fertilizer(BF) at a strong pressure of 1400 kg/cm2.At the same time，the physical mixture of raw fertilizer and organic material(CK) was set as control.The soil electric conductivity(EC)，root composition and root biomass of different diameters were measured at different soil depths on the ridge cross section and at grid points with different distances from the tobacco plant at key growth stages.The Logistic model and exponential model were used to fit the key parameters of root spatial distribution and root biomass accumulation.The effects of brick fertilizer on the electrical conductivity and root growth of flue-cured tobacco were studied.The results showed that the EC of BF treatment was 90.5～281.6 μS/cm higher than that of CK in the soil profile of 2.5～12.5 cm depth at 12.5 cm radius of main root of flue-cured tobacco.The EC of BF was 160.1～392.2 μS/cm higher than that of CK in soil profile of 2.5～17.5 cm depth and 17.5 cm radius of main root system.Within the horizontal radius of 15～20 cm of the main root system，the root weight of BF increased by 150% compared with CK.The root weight in the soil depth of 10～15 cm increased by 26.5%，and the lateral roots in the soil profile of 10～20 cm were more extensional and widely distributed.At 75，90 and 105 days after transplanting，the field root biomass of BF increased by 12.7，11.9 and 9.7 g/plant，respectively，compared with those of CK.The biomass of tobacco leaves was 24.5，13.6 and 17.1 g/plant higher than that of CK，respectively.The BF’S maximum biomass accumulation rates of roots and tobacco leaves were 43.5% and 15.7% higher than that of CK，respectively.For soils with severe leaching，the application of brick fertilizer can improve the nutrient supply intensity，optimize the root distribution pattern and promote the growth and development of flue-cured tobacco.