The invention relates to a traditional Chinese medicine formula for external use, in particular to a formula for external use for treating diabetic foot ulcer wounds, which comprises the following components in parts by weight: 10-20 parts of golden cypress, 10-20 parts of minium, 3-5 parts of borneol, 10-20 parts of lithargite, 2-10 parts of liquorice, 5-10 parts of coptis chinensis, 5-10 parts of ginseng and 12-24 parts of red halloysite. The treatment principles obtained in entropy clustering prescription formula rule analysis include drawing out poison, removing necrotic tissue, promoting granulation, clearing heat, removing toxicity, astringing sores and the like, for example, cortex phellodendri and coptis chinensis have the effects of clearing heat, drying dampness and purging fire for removing toxin, lithargite has the effects of astringing sores and promoting granulation after being externally used, borneol has the effects of clearing heat, removing toxicity and relieving pain, and diabetic foot can be further treated by matching minium, liquorice, coptis chinensis, ginseng and red halloysite. And the treatment effect is improved.