Objective: The purpose of this study was to investigate the effects of 4-week HiHiLo training on the cardiovascular function in obese people. Methods: 12 men with over more than 25% body fat and 12 women with more than 30% body fat were recruited, and then divided into hypoxic (HiHiLo) or normoxic (NOR) group randomly and equally. Hypoxic group stayed 9 hours every night in hypoxic chamber where oxygen content of 16%(simulate altitude of 2200m) at the beginning, then the oxygen content dropped to 14%(simulate altitude of 3300m) gradually within 4 weeks. They were required to be normoxicly trained with the intensity of individual 80% HRmax for 2 hours per day, 6 to 7 days a week. Apart from the same normoxic training loads for 4 to 5 days as normoxic group, hypoxic group were additionally trained under hypoxic circumstance (the oxygen content was 15.5%, simulate altitude of 2500m) for 1.5 hours per day, 2 days a week. Training methods included aerobics, power cycling, running, dumbbell gymnastics and vibration training. The conditions of the normoxic group were fully consistent with hypoxic group, but living and training in normoxic environment. Venous blood samples were collected at the day before experiment, after 9 hours of acute hypoxic exposure and the second and the fourth weekend. The levels of serum CK, CK-MB, cTnI, CHO, TG, HDL-C, LDL-C and GLU were measured. Results: 4-week HiHiLo training caused the levels of CK and cTnI increased first and then decreased significantly while normoxic group had no changes in CK and cTnI. Both of 4 weeks of HiHiLo and normoxic training caused decrease significantly in blood lipids, however HiHiLo had more decrease. Conclusion: HiHiLo is beneficial to myocardial damnificantion recover from the high-intensity training. No significantly additional hypoxia effect could be concluded insufficient simulate altitude and short sojourn duration.