Objective To know about the nutritional status and its influencing factors in middle school students from Yongning County,Ningxia Hui Autonomous Region,in order to provide theoretical basis for scientific intervention on improving nutrition status. Methods A total of 1 091 middle school students were selected to take physical examination and fill out questionnaires. Body mass index (BMI) was used to evaluate nutritional status and Logistic regression analysis was used to analyze influencing factors of nutritional status. Results The detection rates of malnutrition,normal nutrition,overweight and obesity among the 1 091 middle school students were 13.75%,77.18% and 9.07%,respectively. The detection rates of malnutrition and overweight and obesity in boys (16.67%,14.23%) were significantly higher than girls (11.35%,4.84%). The prevalence of overweight and obesity in only children (13.70%) was significantly higher than that in children with siblings (7.55%). The protective factors for malnutrition of middle school students included female (OR=0.611,95%CI:0.422-0.883),maternal occupation of individual business(OR=0.242,95%CI:0.093-0.626) and non-picky eaters(OR=0.602,95%CI:0.420-0.862). No family history of obesity (OR=2.513,95%CI:1.059-5.959) was a risk factor for malnutrition in the area. Meanwhile,the protective factors for overweight and obesity of middle school students included female (OR=0.263,95%CI:0.159-0.433),non-only children (OR=0.432,95%CI:0.257-0.727),and no family history of obesity (OR=0.138,95%CI:0.079-0.241). Sleep time more than 10 hours (OR=13.154,95%CI:1.468-117.850) was a risk factor for overweight and obesity in this area. Conclusions Malnutrition and obesity exist in middle school students in Ningxia Hui Autonomous Region. And the nutritional problems in boys and only children are more prevalent. Thus society,schools and families should adopt targeted interventions to reverse the unfavorable situation of the nutritional status