Abstract: In order to explore influence of high temperature and high humidity environment on human body, such environment was simulated and heat stress experiment conducted by using environmental chamber to obtain data. With temperature for experiment at 34, 36, 38 and 40 ℃,Relative Humidity (RH) at 60%, 70%, 80% and 90%, a comprehensive physiological index F was proposed based on three physiological parameters which were oral temperature (t_c), Heart Rate (HR), skin temperature (t_sk) and two subjective parameters, Thermal Sensation Vote (TSV) and Fatigue Score (FS). Then, experimental working conditions were classified through cluster analysis according to Fscore for each subject, and discriminant function was built using discriminant analysis to establish segmentation threshold. The results show that 16 high temperature and high humidity environments are classified into three types whose range of F score is 28.14-39.76, 39.17-45.21, 44.13-52.39 respectively. And they can be defined as generally harsh environment, moderately harsh environment and severely harsh environment

Key words: high temperature and high humidity environment, heat stress, factor analysis, cluster analysis, classification