Objective Study on relationship between obstructive sleep apnea syndrome(OSAS)and obesity,neck circumsfence(NC),neck length(NL).Methods 89 patients with OSAS were divided into mild group and moderate severe group by apnea hyponea index(AHI).32 non apneic healthy volunteer served as controls.Analysis of correlation and regression were used among AHI and height,weight,body mass index(BMI),NC,NL,NC/NL.Results The weight,BMI,NC,NC/NL in apneic patients were significantly higher than that in the controls.The AHI significant positive correlated with weight,BMI,NC and NC/NL in all patients,and had significant negative correlated with nadir oxygen saturation in sleep .Conclusions The patients with OSAS are more obese and have thicker and shorter necks,it suggests that weight,neck circumference and neck length play an important role in the pathogenic factor of patients with OSAS.