Abstract: The daytime activity budgets of blue sheep (Pseudois nayaur) in Suyukou National Park, Helan Mountain, were studied from November 2003 to October 2004. Blue sheeps activities were recorded by instantaneous and scan sampling methods. We observed feeding, lying, moving, standing and other behaviors from the 10th to 20th days every month with a SJ-1 Event Recorder. Data were collected from 8:00-17:00 in winter, from 7:00-18:00 in spring and autumn, and from 6:00-20:00 in summer. We used the non-parametric Wilcoxon test to compare differences in the time budgets between male and female sheep. Mann-Whitney U and Kruskal-Wallis H tests were used to test activity budgets among age classes. A Kruskal-Wallis H test was also used to make comparisons of time budgets among ecological seasons. Feeding was the principal activity of blue sheep and accounted for 63.49±7.82% of their activities. Lying was the second principal activity, accounting for 19.32±6.79% of their activities. The remaining time was devoted to the other three activities (standing, moving, and other behaviours). The percentage of daytime spent feeding reached its highest level in February, and reached its lowest level in July. Sheep decreased their time spent lying to its highest level in July. During three seasons (spring, summer and autumn), blue sheep showed a morning and evening peak of feeding. Feeding remained at relatively higher levels (over 60%) in winter. Sheep spent a relatively higher percentage of time in other activities in winter than any other seasons. Adult and subadult sheep forage more than did kids; lambs spent more time in lying than did adult and subadult sheep; adult and subadult sheep devoted more time to moving and standing than did kids; kids spent more time standing than did adults. In February, the percentage of daytime spent feeding by male and female sheep reached its highest level. Feeding time spent by males remained a relatively constant level (<70%) in other months. However, time spent feeding by females remained at high levels (>70%) from November in 2003 to February in 2004. There was not a significant difference in the percentage of daytime spent lying between males and females. Male sheep spent more time moving than did females. Like other temperate ungulates, quality and quantity of forage plants, growth and physiological phases all contributed to the daytime activity budgets of blue sheep.