Objectives: This study was conducted to investigate the effects of Morindae officinalis Radix (巴戟) on the spermatogenesis and antioxidant activities in the Sprague Dawley (SD) rat. Materials and Methods: We choose the 2-month-old SD rats, and administered the extract powder of Morindae officinalis Radix once in a day for 28 days. The control rats were administered normal water in the same way and duration. We observed changes of body weight, surgically isolated testis, epididymis, vascular gland and prostate gland before and after administration of Morindae officinalis Radix extracts in SD Rats. Also we compared the testicular tissue, especially seminiferous tubules between the control and treated groups by histochemical methods. In addition, we examined the total, normal, morphologic and motile sperm in the cauda epididymis, and the activity of catalase and peroxidase in the isolated testis tissue. Results: There was no significant difference between control and treatment groups in the body weight, testis, vascular and prostate gland, but the weight of epididymis showed significant difference in the control group. The concentration of total sperm, the motility and normality of spermatozoa was significantly different when compared with the control group, respectively. In the histological examination of testicular tissues, the tendency of increasement of angiogenesis between seminiferous tubules was observed. And the concentration of spermatogonia, primary and secondary spermatocyte and sperm were higher than that of control testicular tissues. Finally, the activity of catalase and peroxidase related inhibitory molecules of oxidation were slightly increased in the treatment group than those of control group. Conclusions: This study shows that Morindae officinalis Radix has the beneficial effect on the concentration, morphology and motility of sperm, the important factor in male fertility. We can suggest that Morindae officinalis Radix has an effect on the spermatogenesis in the SD rat.