Activity of lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) as well as the concentration of myoglobin (Mb) in Gansu Zokors (Myospalax cansus) and SD rats (Rattus norvegicus) under normoxia,2 weeks and 4 weeks of hypoxia were measured through histological and UV spectrophotometer methods.The results showed no significant difference in Gansu Zokor skeletal muscle morphology among different groups,but a significant morphology change in SD rats was observed;After 2 weeks of hypoxia,the muscle fiber was significantly atrophied,the gap was increased,and the structure was more disordered.After 4 weeks of hypoxia,the muscle fiber was broken down,and sarcomere was disordered.Activity of LDH also showed no difference after different hypoxia adaptations in the Gansu Zokor (P>0.05);but compared to SD rat,activity of LDH in the Gansu Zokor was significantly lower after different hypoxia adaptations (P<0.01).The activity of SDH in the Gansu Zokor was lower than that of SD rat,but with no significant difference (P>0.05),after 2 or 4 weeks of hypoxia,the enzyme activity was significantly lower than that of SD rat (P<0.01).The concentrations of Mb in the Gansu Zokor were higher than those in the SD rat in different hypoxia adaptation groups (P<0.05) (P<0.01).We conclude that Gansu Zokor is much more tolerable to hypoxia than SD rat.