Abstract: By preparing the models of castrated male rats, this paper determined the latent period of penis erection and the weight of genital organ among each group of castrated rats administrated apomorphine hydrochloride. The results showed that when the castrated model group administrated apomorphine hydrochloride was compared with the simple model group not administrated apomorphine hydrochloride, the apomorphine hydrochloride used in castrated model group could promote the excitement of castrated male rats' penis, and could cut down the latent period of their penis erection; meantime, there was no obvious difference in the weight and exponents of genital organs between drug-administrated groups and simple model group. Thus it was drawn that apomorphine hydrochloride had an effect on promoting the vital function of castrated male rats and no obvious effects on the tissue of their genital organs.