Giant panda is difficult to breed in captivity due to low oestrus and mating rate, high cub mortality and diseases. Thus, how to improve the mating success of giant pandas in captivity is an important conservation issue. After observation on eleven female and three male giant pandas from Beijing Zoo, Lanzhou Zoo, Chengdu Zoo and Giant Panda Breeding Center during their mating season in 2000–2001, we found that mate preference and sexual selection plays an important role in the mating success in giant panda. Both male and female pandas actively chose their mates. Successful copulations only occurred in those males and females that both showed high frequencies of courting behavior to opposite sex. Of those cases that only male or female showed one-sided high or low frequency of courting behaviour in the keeper-arranged panda pairs in random order, no copulation was observed. Only three out of twenty-four paired pandas successfully copulated. All three copulated female pandas in this study bore cubs. The results show that both male and female giant pandas have to be interested in each other in order to mate, but panda managers and researchers in China historically believed that females play no role in mate choice and that males are the choosy sex. This indicated that mating choice was one of the important factors resulted in unsuccessful copulation and failure of reproduction. We recommend that attention be paid to the mate preference and sexual selection in giant panda when breeding pandas in pens are paired for reproduction in the future.