Objective To investigate the levels of 14 kinds of food allergic specific IgG antibody in eczema and chronic urticaria patients'serum and the role of food allergens in allergic skin diseases and provide scientific basis for clinical treatment and prophylaxis. Methods We used ELISA method to detect the concentration of 14 kinds of food allergic specific IgG antibody in the serum of 900 eczema and chronic urticaria patients and 18 healthy people. Results The food allergen of positive rate in studied group and control group was 90.2% and 11.1%. The positive rate of 14 kinds of food allergic specific IgG antibody in 900 eczema and chronic urticaria patients' serum from high to low was eggs, wheat, shrimp, milk, soja,crab, rice, corn, tomato, chicken, mushroom, beef, pork and ling. The food allergen positive rate in eczema and chronic urticaria patients'serum was 91.9% and 88. 9% ( P >0. 05). The positive rate of shrimp,mushroom and ling in eczema patients'serum was higher than that in chronic urticaria patients'serum ( P <0. 05 ). The positive rate in children's group was 96. 6%, which was higher than other age groups ( P >0. 05 ). The main allergens were egg, wheat and milk in children's group. The sensitization of crab and shrimp increased as people grew up. In 812 positive patients, who were intolerant of three and more than three foods accounted for 53.7%. In 175 follow-up patients, the effective rate was 50.9% in 20 days and 61.1% in 60 days after they avoided the intolerant food. The patients'diet was adjusted according to the test results.In 325 follow-up patients, the effective rate in eczema group was 59.9% in 20 days and 70. 4% in 60 days ( P <0. 05). Thee effective rate in chronic urticaria group was 65.6% in 20 days and 77. 3% in 60 days ( P <0.05 ). Conclusion The intolerant food can be found by detecting serum food allergen specific IgG.It can be used to adjust the diet and relieve the symptom, which is of great importance for preventing and treating allergic skin diseases.