The invention discloses toxicity-removing and tissue regeneration-promoting paste for treating ulcers and a preparation method thereof. The toxicity-removing and tissue regeneration-promoting paste is prepared from the following raw materials in parts by weight: 15-20 parts of coptis, 10-15 parts of Japanese ampelopsis, 5-10 parts of Japanese pagodatree twig, 11-17 parts of radix rehmanniae, 10-15 parts of peach leaves, 13-19 parts of bauhinia purpurea, 8-12 parts of phytolacca acinosa, 15-20 parts of ramie root, 5-10 parts of pangolin, 12-16 parts of polygala tenuifolia, 14-18 parts of chinquapin bark and leaves, 7-11 parts of cimicifuga foetida, 9-14 parts of honeysuckle, 12-16 parts of towel gourd root, 5-10 parts of frankincense, 8-12 parts of myrrh, 10-15 parts of lasiosphaera seu calvatia, 20-30 parts of mirabilite, 15-25 parts of calcite powder, 30-50 parts of calomel, 40-60 parts of rosin, 80-120 parts of white wax and 450-550 parts of sesame oil. The toxicity-removing and tissue regeneration-promoting paste has the efficacies of clearing heat and eliminating dampness, removing toxicity and promoting tissue regeneration, sterilizing and relieving itching, activating blood and eliminating stasis, relieving swelling and stopping pain, discharging pus and eliminating carbuncle, stopping bleeding and accelerating wound healing as well as promoting proliferation and division of neurogliocyte, regeneration of epithelioid cells and blood circulation, has unique and remarkable curative effects on treatment of ulcers, especially suppuration due to infection or wound surfaces which are not healed for a long period of time, and is quick in effectiveness, short in treatment course, high in cure rate, free of toxic or side effects and high in safety.