The invention discloses a radix sophorae flavescentis bath lotion. The radix sophorae flavescentis bath lotion is prepared from the following raw materials in parts by weight: 30-40 parts of radix sophorae flavescentis, 15-20 parts of cortex phellodendri, 15-20 parts of fructus cnidii, 9-12 parts of radix et rhizoma rhei, 20-25 parts of fructus kochiae, 15-20 parts of cortex dictamni, 4-20 parts of a surfactant and 0.03-0.05 part of a preservative. A preparation method comprises the steps that firstly, radix sophorae flavescentis, cortex phellodendri, fructus cnidii, radix et rhizoma rhei, fructus kochiae and cortex dictamni are screened, blended, crushed, soaked, decocted, filtered and concentrated to prepare concentrated liquid, then the surfactant and the preservative are added in proportion to the concentrated liquid, and after stirring, emulsification and inspection, the finished bath lotion is obtained. The radix sophorae flavescentis bath lotion has the advantages that the formula of the radix sophorae flavescentis bath lotion is reasonable, the radix sophorae flavescentis bath lotion has the functions such as clearing away heat and removing toxicity, relieving itching, promoting blood circulation, sterilizing and anti-inflammatory, and can be used for preventing and treating cutaneous pruritus, erosion of vulva and eczema and hemorrhoids, and the bath lotion is simple in production process and convenient to use.