In recent years, the method of camera-trapping has been widely used not only in the investigating on wild animal species diversity, amount and distribution, but also in the research of animal activity rhythm and behavior. We established 60 trapping stations in Gansu Anxi Extreme Arid Desert National Nature Reserve according to kilometer grid method, and did a survey effort of 14657 camera trapping days from September 2017 to September 2018. A total of 1892 independent valid photos of five desert ungulates had been collected for analyzing their activity rhythms. The results show that：(1) In the study area, the total relative abundance index of the five desert ungulates reached to 129.08, and the indices of Blue sheep (Pseudois nayaur) (43.87) and Ibex (Capra ibex) (42.98) were higher than the ones of Argali (Ovis ammon) (25.38), Chigetai (Equus hemionus) (15.62) and Gazelle (Gazella subgutturosa) (1.23). (2) The annual activity rhythms of the five ungulates were consistent, i.e. two activity peaks in a year. Their activities reached the maximum in June, and the second peak was in November or December. (3) The daily appearance of Chigetai at the water-drinking site reached the peak during 22:00-24:00, and the activity peak of Gazelle was during 12:00-14:00 in spring and summer. (4) The diurnal activity rhythm of the Ibex and the Blue sheep were bimodal in every season, and the second

activity peaks of the Ibex were later in dusk than the Blue sheep. Diurnal activity rhythm of the Argali were also bimodal in winter and spring, but had three activity peaks in summer and autumn. Of these three ungulates, the first activity peak was advanced and the last peak was delayed in summer. (5) The night-time relative abundance of Ibex was higher than other ungulates. The activity rhythm of the desert ungulates were influenced not only by the life cycle, behavior and sunshine rhythm, but also by their different habitats.