Objective:To analyze food intolerance status in children in Qingdao by detecting the serum levels of food-specific IgG (sIgG).Methods:In this cross-sectional study, a total of 4 249 children aged 0 to 14 years (all were permanent residents of Qingdao City) admitted to Women and Children′s Hospital Affiliated to Qingdao University from May 2017 to December 2020 for suspected food intolerance were selected as the study objects with the whole sampling method. According to the age, the objects were divided into 4 groups: 0-<1 year group (440 cases), 1-<3 years group (1 761 cases), 3-<6 years group (1 193 cases), and ≥6 years group (855 cases). Positive condition of serum sIgG antibodies of 14 kinds of food in the children were detected by enzyme-linked immunosorbent assay. Chi-square test was used to compare the positive rate of the antibodies among different foods, gender and age groups.Results:The total positive rate of food sIgG antibody in 4 249 children was 95.32% (4 050/4 249), the highest positive rate was found in eggs (81.50%) and the lowest positive rate was found in pork (1.15%). The positive rates of sIgG antibody in milk (54.98% vs 49.69%, χ2=11.627), crab (5.59% vs 3.71%, χ2=8.049) and shrimp (4.62% vs 2.75%, χ2=9.784) in boys were significantly higher than those in girls, and the positive rates of sIgG antibody in tomato (49.19% vs 45.54%, χ2=5.510), cod (8.53% vs 5.96%, χ2=10.512) and beef (2.58% vs 1.70%, χ2=3.959) in girls were significantly higher than those in boys (all P<0.05). The total positive rate of sIgG antibody in 14 foods was the lowest in 0-<1 year group (89.09%), and it was the highest in 3-<6 years group (96.98%) ( χ2=63.950, P<0.001). The highest positive rate in 0-<1 year group was found in tomato (56.36%), and it was eggs (85.29%, 88.94%, 85.50%) in all the other 3 groups. The positive rates of corn and beef decreased with age ( χ2=44.098, 20.106, P<0.001), while those of cod and mushroom increased with age ( χ2=32.315, 40.338, P<0.001). The positive rate of wheat (57.13%, χ2=42.273), tomato (57.01%, χ2=209.862), soybean (24.99%, χ2=92.580), crab (6.81%, χ2=33.201), shrimp (6.25%, χ2=47.863) were all the highest in 1-<3 years group among the 4 groups (all P<0.001), and the positive rate of chicken was the highest in 3-<6 years group (7.88%, χ2=29.875; P<0.001). Conclusions:Children in Qingdao have a high level of food intolerance, and the highest positive rate is for eggs. Milk, crab and shrimp should be focused on for boys, while tomatoes, cod and beef shoud be paid more attention to for girls. Children of different ages have different kinds of food intolerance, and their diets should be adjusted reasonably according to the characteristics.