Objective To investigate the scrotal ultrasonographic features of acquired obstructive azoospermia of proximal deferent duct. Methods Ninety-two cases of acquired obstructive azoospermia of proximal deferent duct (case group) were evaluated by scrotal ultrasonography. Among the 92 cases, 79 were epididymal post-infective obstructive azoospermia, the other 13 were vas deferens post-surgical obstructive azoospermia(one side was post-surgical, while the other was post-infective in 2 cases). The ultrasonographic features of testis, epididymis and scrotal segments of vas deferens were observed. Another 65 cases with normal semen were served as control group. Results There was no significant difference in testicular volume between case group and control group （P>0.05）. The ultrasonographic appearance was abnormal in 184 epididymis of all the 92 cases, and the epididymal head, body and tail were all significantly thicker than those of control group (P<0.05). The epididymal duct in the thickening of epididymis were ectatic, exhibiting microreticulate changes, with inner diameter of 0.03 cm. Thirty-nine (24.4%) post-infective obstructive epididymis presented high echo inflammatory nodules. The mean inner diameter of scrotal segments of vas deferens of 159 sides （99.4%）in 160 epididymal post-infective obstructive azoospermia was similar to that of the control group. The vas deferens of the proximal surgery side were all expanded in 24 vas deferens post-surgical obstructive azoospermia. Conclusion Because of different location of obstruction and causes in acquired obstructive azoospermia of proximal deferent duct, there are different features of the epididymis and vas deferens of the ultrasonographic appearance, and scrotal ultrasonography can provide credible sonogram evidence for the diagnosis.