Objective Observation on the effect of ultramicro powder of Ophiocordyceps xuefengensis on the fertility of SD rats and the development of early embryo. Method According to the guiding for evaluation of drug reproductive toxicity, the toxicity of Ophiocordyceps xuefengensis superfine powder on the fertility and early embryo development of SD rats was tested. Results During the experiment, the intake and body weight of each group increased normally, and there was no significant difference in mating, fertility and early embryo development between the experimental and control group. There was no significant difference between the groups. Conclusion Under this experimental condition, the Ophiocordyceps xuefengensis superfine powder has no toxic effect on the fertility and early embryo development of SD rats.