To explore the application of human body exergy analysis method in evaluating thermal comfort conditions of indoor environment, a more feasible method based on the definition of metabolic exergy was proposed to calculate human body metabolic exergy rate after comparison with two existing calculation methods. Then a new two-node human body exergy analysis model validated by ASHRAE thermal comfort database was proposed. Results indicate that exergy rates were more precise if the sum of warm and humid metabolic exergy rates was calculated based on clearly-defined energy metabolism by heat and moisture. The proportion of exergy consumption rate to metabolic rate was greater than that of the exergy exchange rate. The exergy exchange rate mainly consisted of convection and radiation exergy rate when the operative temperature was 25 ℃, while it consisted of evaporation and respiration exergy rate at 32 ℃. The exergy consumption rates reached extreme values at both lower and higher operative temperatures, and hence using the index alone as a thermal comfort evaluation parameter was inappropriate. It was more appropriate to consolidate exergy exchange rate with exergy consumption rate as a human body thermal comfort estimating index. The minimum values of aforementioned two terms, for a given indoor parameter, appeared at a greater outdoor air temperature and a lower outdoor relative humidity. The outdoor air temperature had a stronger impact on exergy exchange rate and exergy consumption rate than outdoor relative humidity.