Abstract： Objective:To investigate the effect of anoxic cold environment at 4500 m altitude on female men-struation.Methods:From March 1 to March 20,2023,women in a unit at an altitude of 4500 meters were selected for reproductive health questionnaire survey,and were divided into≤6 months group,6 months to 12 months group and≥12 months group according to altitude exposure time.The changes of menstruation in each group were analyzed to explore the relevant influencing factors.Results:The total incidence of abnormal menstruation in working women in hypoxic cold environment was as high as 66.14%,and there was no statistically significant difference between the groups at different high-altitude exposure times(P＞0.05).The highest incidence of dys-menorrhea among the types of menstrual changes was 61.90%,but there was no statistically significant differ-ence between the groups at different high altitude exposure times(P＞0.05).There was a statistically significant difference(P＜0.05)in the proportion of insufficient sleep for at least 3 days per week,nervousness and anxiety,and training during their menstrual period in the women who experienced changes in their menstrual cycle com-pared to those who did not.Conclusions:Hypoxic cold environment can lead to the change of female menstrua-tion,and it is combined with sleep deficiency,tension and anxiety,and menstrual exercise.