Abstract: The morphological observation of the cerebrums of 3-month-old yaks provided morphological information for further exploration of yak nervous system＇s adaptability to areticalpine hypoxic environment. Through anatomical methods, the cerebrums of four 3-month-old yaks were dissected, observed, described, and drawn. As shown by the results, the cerebrums of yak calves were flat, and the gaps between gyri and sulci were not clear. The cerebrums were fiat in the first half and expanded to both sides in dorsolateral central part of cerebrums. There was a short small sulus, deep or shallow, in the lateral fossa of cerebrum. The optic ehiasm was obtuse. So there were significant differences between the cerebrum of 3-month-old yaks and that of adult yaks.