The invention relates to a medicine for external application used for treating gout and a preparation method, the medicine for external application comprises the following traditional Chinese medicines: smallflower galinsoga flower, buckwheat root, philippine flemingia root, glabrousleaf pittosporum leaf and Paris polyphylla Smith; the above traditional Chinese medicines are respectively immersed in a boiled rice vinegar, and are inoculated to Acetobactersp. GLYSM66 CCTCC NO: M2011238, after fermenting through different fermentation times, and then a fermentation broth is blended to prepare the medicine. The medicine for external application has the function of dredging the channel and activating meridian, can rapidly reduce the uric acid level in blood of the gout patients, and has the advantages of fast pain relieving effect, good curative effect, low cost, no toxic and side effects and simple preparation method.