The invention discloses Chinese medicinal shampoo with a blood pressure lowering function and a preparation method thereof. The shampoo is prepared from the following components in parts by weight: 10 to 20 parts of anionic surfactant, 2 to 5 parts of ampholytic surfactant, 3 to 6 parts of nonionic surfactant, 5 to 10 parts of medicinal extract, 1 to 2 parts of quaternary ammonium salt conditioning agent and 0.5 to 1 part of chelating agent, wherein the medicinal extract is prepared from the following components in parts by weight: 15 to 30 parts of kudzuvine root, 15 to 30 parts of fructus evodiae, 10 to 20 parts of chrysanthemum, 15 to 30 parts of astragalus mongholicus, 5 to 10 parts of red-rooted salvia root, 5 to 10 parts of monkshood, 5 to 10 parts of dry ginger, 5 to 10 parts of peach kernels, 5 to 10 parts of safflower and 5 to 10 parts of hemlock parsley. According to the shampoo, nerve endings on the scalp are stimulated by a hair washing and massaging mode, so that capillary vessels are dilated, pores are opened, the blood supplying situation is improved, the osmotic absorption of effective components of the medicament is promoted, the side effects of a traditional insomnia treatment medicament to stomach, intestines and liver can be avoided, the destruction to the pharmaceutical effect due to detoxication effect of digestive juice and liver can be overcome, and in the prescription of the shampoo, a nitrogen-containing surfactant is applied. Therefore, the anticorrosion of the shampoo is improved, and the problem that shampoo containing natural products is hard to store is solved.