Burn four degrees of division in clinical medical care practice summed up the mnemonic can be summarized as Ⅰ degree red, Ⅱ degree herpes, Ⅲ degree skin all bad, four degrees deep into the tendons musculoskeletal, etc.. Its specific embodiment is as follows: 1, Ⅰ degree burns: also known as erythematous burns. Local skin redness, slightly swollen, burning-like pain. 3 ~ 5 days epidermal folding, peeling, healing new epithelium bright, red and tender. 2, II degree burns: also known as blistering burns. ① shallow Ⅱ degree burns: burns due to local capillary dilation, congestion and its redness, there are blisters of varying sizes formed, the blister fluid is clear and transparent, pale yellow or protein coagulation-like gel. The blisters that have broken down may reveal a red, moist base, and the patient has significant pain. ② Deep degree II burns: local swelling, epithelial whitish or brownish yellow, with scattered small blisters, the base of the broken blisters is slightly moist, the color is red, white or red in white, and many red dots or small vascular branches are visible, which is due to capillary expansion and congestion. Deeper deep II degree burns can be seen due to the embolization of the coagulated vascular network, dull sensation, pain is not obvious. 3, Ⅲ degree burns: also known as crusty burns. Local waxy white, brown or charcoal black, or charcoal-like, dry and blister-free, no pain, tough leather-like hard, visible coarse vascular network coagulated under the crust, which is caused by the embolization of veins under the fat layer. 4.Fourth degree burns: deep to the tendons musculoskeletal etc. .