Abstract: In November, December 2007 and March 2008, we studied the diurnal activity budgets of the Mongolian Gazelle (Procapra gutturosa) using group-scan-sampling for the time before, during and after the rut around DaLai Lake, Inner Mongolia. The activities of Mongolian Gazelle were divided into 6 categories: feeding, standing, moving, lying, rutting and others. The results showed: 1) Before the rut, the major behavior of the female was feeding, the time budget of feeding occupied 44.9±3.8% of all diurnal time, the lying time was 32.3±4.8%; During the rut the females spent 43.5±4.0% on feeding and 29.2±2.9% on lying; After the rut the time budget of feeding occupied 46.2±3.1% of all diurnal time, the lying time was 28.0±4.8%. Activity budgets of the female on standing, rutting, others changed significantly among the three periods (P<0.05)，but activity budgets on feeding, moving, and lying did not change significantly among the three periods (P>0.05). 2). Before the rut, the major behavior of the males was feeding, the time budget of feeding occupied 52.6±3.8% of all diurnal time, the lying time was 13.4±6.4%; During the rut the males spent significantly less time on feeding (17.5±2.8%) and more time on lying (24.2±4.1%) compared with before the rut. After the rut, the time budget of feeding occupied 29.8±4.8% of all diurnal time, while the lying time was 44.2±4.7%. Activity budgets of the male on feeding, standing, moving, lying, rutting, others changed significantly among the three periods (P<0.05). The time budget on feeding and lying reflects on energy balance strategies. We conclude from the results that; females do not change their strategy significantly among the three periods - they try to increase their energy intake; before the rut, the male is the same as the female, but during and after the rut, the males adopt an energy saving strategy to optimize their energy balance; males aim to save energy by spending more time lying.