Plaster for treating diabetes and preparation method of plaster

The invention relates to plaster for treating diabetes. The plaster comprises the following steps: (1) selecting radix astragali, radix codonopsis, fructus foeniculi, cordyceps sinensis, corn cervi pantotrichum, callorhinus ursinus, vegetable oil and yellow lead; (2) selecting radix gaultheriae cumingianae, herba phrymae leptostachyae, herba hedyotidis, longpeduncle kadsura stem, manis pentadactyla, bungarus parvus, vegetable oil and yellow lead; and (3) extracting medicine: separately pouring the medicinal raw materials and vegetable oil prepared in two times into a pot, soaking for two daysand two nights, then heating with low fire, continuously stirring, frying the medicine to be dry yellow, and removing the herb residue; heating and decocting the medicine oil, continuously stirring, when blue smoke rises from the oil and is changed into thick smoke, collecting the oil, dropping into water until the oil droplets are not dispersed, extinguishing the fire, taking the oil pot away from the fire, feeding the y