Objective: To investigate the clinical significance of accessory hepatic vein (AHV) pressure reduction in treatment of Budd-Chiari syndrome (BCS). Methods: The clinical data of 27 BCS patients treated during March 2007 to July 2015 were retrospectively analyzed. Of the patients, 11 cases were male and 16 cases were female, with an average of (46±8) years old; 9 cases had lesions in the opening of AHV, 12 cases had occlusion in the inferior vena cava (IVC) and 6 cases had mixed lesions of AHV and IVC. Results: All patients underwent venography and manometry of the AHV and endovascular treatment. Nine patients with AHV disease underwent balloon dilatation angioplasty of the AHV, and their preoperative AHV pressure dropped from (25±4) cmH2O to (17±3) cmH2O; in the 12 patients with IVC disease, 10 cases underwent balloon dilatation angioplasty of the IVC and 2 cases underwent open surgery, and the preoperative AHV and intrahepatic IVC pressure decreased from (27±6) cmH2O to (15±4) cmH2O and from (27±5) cmH2O to (14±3) cmH2O, respectively; in the 6 cases with both AHV and IVC involvements, the preoperative pressure of AHV and IVC declined from (28±6) cmH2O to (14±4) cmH2O and from (26±5) cmH2O to (13±4) cmH2O, respectively. The abdominal symptoms were significantly relieved 3 days after operation in all patients and the edema in lower limbs was remarkably alleviated in those with IVC lesion, with treatment effective rate of 100%. No complications such as bleeding and pulmonary embolism occurred. Twenty-three patients were followed up for 4 to54 months, doppler ultrasound at 6 months after operation showed that the patency rate of original lesion was 100% and, at a later time, IVC re-occlusion occurred in 2 cases which were resolved by second balloon dilatation. Conclusion: AHV pressure reduction can help to alleviate the symptoms of BCS patients, and attention should be paid to the existence of the AHV and the treatment of its problems.