Use of 5α-androstane-3β,5,6β-triol and analogs thereof in the preparation of a drug for the prophylaxis or treatment of an altitude sickness caused by hypobaric hypoxia is provided, so as to provide a new drug for the prophylaxis or treatment of an altitude sickness. Researches revealed that 5α-androstane-3β,5,6β-triol treatment can effectively reduce vasogenic edema of brain tissue of Macaca fascicularis caused by hypobaric hypoxia, reduce the increased cerebral water content, and protect from neuronal vacuolar degeneration caused by hypobaric hypoxia, therefore it can improve neurological dysfunctions caused by hypobaric hypoxia and is useful in prophylaxis or treatment of an altitude sickness.