The effect of layered and reduced fertilization on the growth of peanut root system was systematically studied in the field experiment，using Qinghua No.7 as the material.The results showed that the total root length，root surface area，average root diameter，root volume and dry matter accumulation were increased by layered and reduced fertilization. The effect of promoting root growth in 20～40 cm soil layer was significantly better than 0～20 cm soil layer.The total root length，root surface area and root volume of 0～20 cm and 20～40 cm soil layers increased by 10.9%～16.6%，9.3%～13.5%，5.4%～15.1% and 12.3%～19.6%，17.9%～30.1%，3.7%～20.0%，respectively compared with CK when the root growth was the highest (August 1)，in the 20～40 cm soil layer，and the growth rate was 2.5，11.8 and 2.5 percentage points higher than that in the 0～20 cm soil layer.With the same fertilizer amount，the promotion effect of root growth in 20～40 cm soil layer was obviously better than that in 0～20 cm soil layer； the effect of three-layer fertilization was better than that of two-layer fertilization with the same amount of fertilizer； while with the same fertilization layers，the root indexes did not decrease significantly with the decrease of fertilization amount.The study indicated that two-or three-layer fertilization with 10%～20% reduction of fertilizer can be used as effective measures to improve the utilization rate of fertilizer and strengthen root system and plant.