Background and Objectives：Attention-deficit/hyperactive disorder (ADHD) is one of the most common neuropsychiatric disorders in children characterized by a triad of symptoms involving age-inappropriate behaviors with attention, impulse control and hyperactivity. It is estimated to affect 3-7% of school-aged children. Most of previous studies focused on the non-modifiable factors on ADHD such as familial-genetic factors, neurotransmitter defects (dopamine, serotonin and noradrenaline genes disorder), pregnancy or delivery complications. Previous studies have linked ADHD and some environment factor (such as nutrient deficiency or allergy status), but they focused mostly on single factor at a time. Our study investigated the relationship between ADHD and children’s nutritional status (eating patterns) and allergy taking into considerations Traditional factors by using a multi-variate approach. Methods：This match case-control study recruited 216 ADHD and 216 age, sex, height and weight-matched control children, aged 6-12 years which complete data. Differences in characteristics between children with ADHD and control were compared using t-test and chi-squared test. Twenty-eight were measured from whole blood or serum specimen, fifteen of which were significantly different between cases and controls by t-test. Using factor analysis, 15 biochemical profiles were grouped into 7 factors. Meanwhile, using factor analysis, the food frequency of 20 food groups was grouped into 5 factors which were used to construct dietary patterns. The association between ADHD and allergy, poor biochemical profile, dietary patterns were assessed by multiple logistic regression after adjusting potential confounding factors. Results：ADHD was negatively associated with hemoglobin status, serotonin and related nutritional factor (folate, B6, B12 and serotonin), non-PUFA factor (high MUFA and low SFA) and antioxidant factor. ADHD was positively associated with mineral factor (a linear combination of high phosphorus and low ferritin), n-6/n-3 ratio, and Allergy. Children with a greater number of malnutrition patterns were more at risk for ADHD. Meanwhile, ADHD was positively associated with unhealthy eating patterns, which included high intake of low-quality foods (e.g. ice, sweets, and fried foods) and low intake of low-quality foods (e.g. vegetables, fruit, meat, fish, eggs, soybean and milk). Children with a greater number of unhealthy eating patterns were more at risk for ADHD. Conclusions：The study has found that ADHD may be in part explained by their allergic conditions and poor nutritional status which maybe associated with their unhealthy eating patterns, implicating that good nutritional status/healthy eating patterns and controlling allergic symptoms are important in mitigating ADHD.