We observed the diurnal activity rhythm and duration of each behaviors of Przewalski’s horses in breeding period and post-breeding period by using focal animal sampling methods during April to August, 2011 at Xinjiang Wild Horse Breeding and Research Center. We tested the differences of time budget spent in each behaviors by male and female and the diurnal activity rhythm between males and females by the One-way ANOVA test. We totally made 14 688 min,valide observations (8 736 min in breeding period and 5 952 min in post-breeding period) and found out (1) during breeding season both males and females same time in feeding, drinking and standing (P>0.05), but males spent less time in resting, grooming and more timein moving and other behavior (P<0.05); (2) The difference in diurnal activity rhythm between males and females were showed in moving, grooming and other behavior (P<0.05), but no difference in the rest activity rhythms between the two genders; (3) Mating behavior was hardly occurred in daytime, and in one family group no any two females were mated by the same male in the same day. That indicated the possibility of one stallion mate with two or more female horses in one family group was very rare.