Objective To examine the situation of iodine nutritional status and the prevalence of hypothyroidism in Pinggu District of Beijing City,and analyze the illness-related factors.Methods A cross-sectional survey was performed in 734 adults who had lived more than five years in Pinggu District,a random urine sample was collected in the morning from each adult,urine iodine was tested via the arsenic cerium catalytic spectrophotometry method (WS/T 107-2006);edible salt samples were collected,salt iodine was tested via the method of direct titration (GB/T 13025.7-1999);fasting blood samples were collected,electrochemiluminescence was used to measure three free triiodothyronine (FT3),free thyroid hormone (FT4),thyroid-stimulating hormone (TSH),thyroglobulin antibodies (TgAb) and thyroid peroxidase antibody (TPOAb);automatic biochemical analyzer was used to measure triglyceride (TG);high pressure liquid phase method was used to measure glycosylated hemoglobin (HbAlc).The results of routine physical examination,thyroid examination by color Doppler ultrasound and questionnaires were collected.Results A total of 696 urine samples were collected,the median of urine iodine was 125.25 μg/L,and the values of male (287 cases) and female (409 cases) were 125.19 and 125.79 μg/L,respectively.Forty-nine non-iodized salt samples (6.7％),647 qualified iodized salt samples (88.1％),and 38 unqualified iodized salt samples were detected (5.2％),respectively.Subclinical hypothyroidism (58 cases,89.2％) in all hypothyroidism (65 cases) was the most common hypothyroidism.Independent risk factors for hypothyroidism of male were increased TG [odds ratio (OR) =3.298,95％ confidence interval (CI):1.112-9.785]and over 60 years old (OR =8.657,95％CI:1.015-73.863);independent risk factors for hypothyroidism of female were physical work (OR =3576,95％CI:1.323-9.670),increased TgAb (OR =2.306,95％CI:1.099-4.841) and diffused change of thyroid (OR =5.177,95％CI:1.944-13.787).Conclusions The iodine nutritional status of residents in Pinggu District of Beijing City is good.Main type of hypothyroidism is subclinical hypothyroidism.Age,diffused change of thyroid,etc.are the influencing factors of hypothyroidism.