The aim of this study was to investigate the level of secretions of prostate and seminal vesicles and its association with the expression of AQP0, 1, 4, 5, 6 and 8 in castrated rats. Eight-week-old male Sprague-Dawley (SD) rats (n = 18) were randomly divided into control group, castrated rats group and castrated followed testosterone replacement group. Four weeks after surgery, the secretions and expression of AQP0, 1, 4, 5, 6 and 8 of prostate and seminal vesicles were determined. Serum testosterone was significantly lower in castrated groups than in control and testosterone replacement groups (P < 0.05). The level of prostate and seminal vesicle secretions and the expressions of AQP0, 1, 4, 5, 6 and 8 in prostate and seminal vesicles were significantly lower in castrated group than in control and castrated followed testosterone replacement groups (P < 0.05). The decreased prostatic and seminal vesicle secretions in castrated rats may be related to the decrease in AQP0, 1, 4, 5, 6 and 8 in prostatic tissue and seminal vesicles.