1. All patients with Behcet's disease will have recurrent painful oral ulcers, which are mainly located at the edge of the tongue, the surface of the tongue, the cheek, the soft palate, the lips and even the pharynx and tonsils, ranging in size from rice grains to soybeans, and can appear individually or in batches, and disappear without leaving a trace in about 7 ~ 10 days; 2, more than 70% of patients will have genital ulcers, the number of attacks is relatively small, but the area is larger and deeper than oral ulcers, and the pain is very intense, which is common in vulva, vagina, cervix, perianal region, scrotum and penis; 3. Skin erythema can occur on the face, neck, upper limbs and lower limbs. Skin erythema has the characteristics of induration and pain. The biggest feature is that there will be red induration in case of minor trauma, which can also become pustules after infection; 4, may involve the eyes, manifested as blurred vision, decreased vision, eyeball pain, eyeball redness and congestion, in addition to floaters, foreign body sensation or headache. The most typical manifestation of the eye is iridocyclitis, which can be combined with pus in the anterior chamber. 5. There can also be arthritis, which is manifested as inflammation of a single asymmetric joint.