Objective To explore the effect of oligosaccharides of Morinda officinalis to protect the reproductive ability of mice. Methods The test were randomly divided into five groups， control group（constant volume distilled water）， model group（deficiency of kidney yang）， oligosaccharide extracted from Morinda officinalis high-dose， medium-dose and low-dose groups group（the dosage of OMO was 0.02 g、 0.04 g、 0.08 g， respectively） with intragastrical administration. The mice model was induced by tired excessive sex not section method. After 6 weeks， the reproductive hormone levels， MDA， SOD and GSH-Px in mice were detected. Results The middle and high does of oligosaccharide extracted from Morinda officinalis group was compared to the model group as follows：the containments of FSH， LH， T and GnRH in the blood became higher（P＜0.01）， containment of MDA in the epididymis tissue was lower， and concentrations of SOD and GSH-Px increased（P＜0.01）. Conclusion The oligosaccharides of Morinda officinalis might regulate the function of spermatogenic process by regulating the pituitary-hypothalamus-gonadal axis， and enhance the body antioxidant activity and epididymis， and thus play a role in the protection of epididymal sperm from oxidative damage.