Objective: To explore the characteristics and differences of energy expenditure of stair climbing in male university student with different BMI groups and under varying load capacity. Methods: A total of 24 male university students aged 20 to 30 years were recruited from universities in Beijing. Participants were divided into normal weight group and overweight group according to BMI. The energy expenditure of climbing stairs and rest energy expenditure were measured by Cortex MetaMax 3B portable gas metabolic analyzer. The load for climbing stairs from 0 to 5 kg. Results: The energy expenditure during stair climbing with a load of 5 kg in overweight group was significantly greater than without load ( F=9.44, P <0.05). Greater physical load is needed for the same energy expenditure among overweight male university students than normal weight students. The energy expenditures during stair climbing with loads of 4 kg and 5 kg in normal weight group were significantly greater than without load ( F=7.47, P <0.05). The net energy expenditures per unit weight during stairs climbing carrying 3 kg load in overweight group and 4 kg load in normal weight group were significantly higher than without load and load with 1 kg ( F=3.39, 3.79, P <0.05). When climbing up stairs with same load, the energy expenditure in both overweight and normal weight group were greater than those of stair descending. Conclusion Stair climbing with mderate load (3 kg) for overweight male students, and higher load (4-5 kg) for normal weight male student are needed for weight control.