Cistanche deserticola (CD) has been considered as a tonic agent on reproductive function for thousands of years. The effects of CD extract on penis erectile response were investigated in present study. After castration surgery, rats were treated intragastrically with CD extract (0.45, 0.90 and 1.8 g/kg) daily for four weeks. Penis erectile response was measured and the serum hormones were assayed at the end of the experiment. It was evaluated that the erectile latency became longer and the erectile duration shorter significantly in castrated rats compared to sham operated controls. However, CD extract shortened the erectile latency and prolonged the erectile duration to minimize the negative effects of castration. At the dosage of 0.9 g/kg, CD extract regulated the serum luteinizing hormone concentration approach to normal level in castrated rats. These findings indicated that CD facilitated the penis erectile response and modulated the serum hormone level to some extent.