The invention relates to Bi-syndrome external plaster and relates to Huoxue Xiaozhong Zhitong plaster, in particular to a pure herbal pharmaceutical for strengthening spleen and kidney, dispelling cold and damp and activating blood to alleviate swelling. A preparation method of the plaster includes: soaking yellow lead, Chinese angelica root, Himalayan teasel root, root of bidentate Achyranthes, suberect Spatholobus stem, Chinese clematis root, cassia twig, Acanthopanax root bark, crude aconite root, crude kusnezoff monkshood root, divaricate Saposhnikovia root, wooly datchmanspipe herb, garden balsam stem, hooked Uncaria twig, obscured Homalomena rhizome, root-bark of Chinese hydrangeavine, common club moss herb, incised Notopterygium rhizome, doubleteeth pubescent angelica root, Chinese wild ginger, fruit of Chaenomeles speciose, Qin jiu, pseudo-ginseng, fingernail, carbonized hair and mulberry ridge in sesame oil, pouring root of Angelica dahurica, Szechuan lovage rhizome, raw frankincense and crude myrrh into a pot when the carbonized hair softens and lumps, performing filtering when the carbonized hair feathers, adding the carbonized hair into the pot, adding tung oil into the pot, performing decocting, slowly adding the yellow lead, performing stirring under heating until melting, stopping heating, immersing oil into cold water, continuously adding water for flushing and cooling, taking out and air-drying kneaded wet dough when soaking is sufficient, performing heating with low fire until softening, evenly applying it to clean cloth, and directly applying the plaster to an affected part.