A Yi-nationality medicine water-based plaster, a preparing method thereof and applications of the plaster are disclosed. The water-based plaster is prepared by subjecting raw materials including 50-110 parts by weight of orientvine vine, 40-110 parts by weight of whitetomentose ainsliaes herb, 40-110 parts by weight of ipomoea cairica (L.) Sweet, 60-110 parts by weight of bark or leaves of lindenleaf torricellia, 20-60 parts by weight of paris root, 20-60 parts by weight of Asian lopseed, 10-50 parts by weight of root of delavay dobinea, 30-70 parts by weight of chloranthus holostegius, 20-60 parts by weight of red camphorwood, 10-40 parts by weight of giant knotweed rhizome and 30-70 parts by weight of toddalia asiatica to pretreatment, decoction and after-treatment steps. The applications are applications of the water-based plaster in preparing medicines for external application for treating rheumatism swelling and pain, injuries from falls, fractures, contusions and strains, and sore, ulcer and pyogenic infection diseases. Yi-nationality wild medicine materials unique in Yunnan are adopted, a prescription is prepared carefully, a dosage form is modified, and a modern hot melt adhesive is adopted as a matrix to prepare the novel plaster for external application, which has Yi-nationality medicine characteristics and good curative effects and which is convenient to use and easy to carry and store. The plaster has advantages of using convenience, capability of being repeatedly applied without the need of heating, a good fixation property, no leakage, portability, convenient storage, and the like.