The behavioural time budget affected by many factors is a trade-off between the resources acquisition and the risk defense in animals. During mating seasons, behaviours of male Tibetan antelopes were observed by the focal animal sampling in Kekexili National Nature Reserve, and all behaviours were divided into five categories, foraging, vigilance, resting, moving and ‘others’. By comparing differences in the behavioural time budget between before (2003-2004 mating season) and after (2017-2018 mating season) the operation of Qinghai-Tibet Railway, We discussed effects of the Qinghai-Tibet Railway on the behaviours in male Tibetan antelopes. Then, the effects of age on the behavioural time budget in male Tibetan antelopes were analyzed based on the data obtained during 2017-2018 mating season. According to our results, male Tibetan antelope spent more time on foraging and ‘others’ and less time on vigilance and resting after the operation of Qinghai-Tibet Railway, which indicated that the male Tibetan antelopes have gradually adapted to the emergence of the Qinghai-Tibet Railway. Due to different roles in mating groups, adult males owned more females than subadults and should maintain the stability of mating groups by increasing the vigilance and moving and decreasing the foraging and resting.