Objective:To study the size difference of bilateral axillary vein in adults, and to provide basis for the design of interventional surgical treatment.Methods:From December 2017 to December 2018, 145 inpatients (117 cases of hypertension, 28 cases of heart failure) and 87 healthy volunteers were selected from the Second People's Hospital of Lianyungang as study objects.The size of bilateral axillary vein of each study object was measured and the difference was statistically analyzed.Results:Among the 232 subjects, the dominant hand was the right hand, accounting for 95.7% (222/232). There were no statistically significant differences in the size of left and right axillary veins (all P>0.05). There were no statistically significant differences in the other indicators except age between the two groups (all P>0.05). The diameter of axillary vein was (0.67±0.15)cm in male and (0.53±0.13)cm in female, the difference is statistically significant( P=0.000). In the healthy control group, the dominant, non-dominant and large cross-sectional areas were (0.54±0.17)mm 2, (0.54±0.15)mm 2, (0.60±0.16)mm 2, respectively, which in the hypertension group were (0.55±0.14)mm 2, (0.54±0.14)mm 2, (0.59±0.14)mm 2, respectively, which in the heart failure group were (0.54±0.16)mm 2, (0.56±0.19)mm 2, (0.59±0.1)mm 2, respectively, there were no statistically significant differences among the three groups (all P>0.05). Conclusion:The difference is not obvious in the size of bilateral axillary vein, and there is no correlation between the size of bilateral axillary vein and dominant hand.The size of axillary vein in adults of different genders is different, and the size of axillary vein can be estimated by the gender of subjects, but not by the dominant hand or other data.