Objective To investigate relationship between urinary iodine level and thyroid diseases in Liaocheng city.Methods Level of serum TSH,FT3,FT4,TPOAb,TGAb and urinary iodine in thyroid disease group and normal control group was detected respectively.Results The median concentration of urinary iodine in normal control group in Liaocheng was 108μg/L.The median urinary iodine level in patients with thyroid dysfunction and thyroid nodal diseases was higher than that in normal control group(P<0.01).In patients with thyroid dysfunction and thyroid nodal diseases,the concentration of urinary iodine Was above 300μg/L and distribution frequency Was much higher than that in control group(P<0.01).There was no correlation between urinary iodine and thyroid function or thyroid nodule(P>0.05).Conclusions Iodine uptake in Liaocheng is sufficient.Additional uptake of iodine increases the incidence of thyroid diseases.Urine iodine detection helps to guide iodine supplementation in individual.