Objective:To investigate diameters and location of inferior vena cava in 100 normal adults by CT,and evaluate its the values on clinical application. Methods:The maximum and minimum diameters of inferior vena cava of 100 normal adults were measured. The distance from the X-axis(in first liver hilar level,along foreside of vertebra drawing a horizontal) or Y-axis(along starboard of vertebra drawing a perpendicular) to inferior vena cava was measured. The angle between the maximum diameter of inferior vena cava and the X-axis was measured also. All datum were dealed with statistics. Results:At the level of right atrium,the minimum diameters of IVC was relative invariablenes according to age and gender(P > 0.05). The upper limits of 95% cases were less than 3.0 cm in different groups disparted on age and gender. The maximum diameters of IVC and the ratio of the maximum and minimum diameters were variable in different groups(P < 0.05). At the level of the first liver hilar,the minimum diameters of IVC didn’t change with age(P > 0.05),but changed with the genders(P < 0.05). But the upper limits of 95% were less than 22 mm. Moreover the maximum diameters of IVC and the ratio of the maximum and minimum diameters were variable in different groups disparted on age and gender(P < 0.05). The distances from the X-axis and Y-axis to inferior vena cava had no changes in the different groups on age or gender(P > 0.05). The upper limits of 95% were less than 2.5 cm and 1.0 cm,respectirely. The angle between the maximum diameter of inferior vena cava and the X-axis was 31°±5°,without diffences in groups divided by age(P > 0.05),but changed with gender(P < 0.05). But the upper limits of 95% were less than 60°. Conclusion:The minimum diameter of IVC can be taken as a sensitive indexe to evaluate the size of IVC. The range of the location of normal IVC and the angle conseructed with the X-axis were ascertainable in CT. It can offer reference for judgement of the change of IVC’s location induced by hepaorenal recess disease.