Abstract: In order to quantitatively study the temporal and spatial variation characteristics of human comfort index in Hunan Province, daily meteorological data of 32 national meteorological stations in Hunan Province from 1977 to 2011 were selected to calculate the human comfort index and the climate characteristics and climatic tendency rates of different comfort level days in Hunan Province, the inverse distance weight method was used for spatial interpolation analysis, and Mann-Kendall method was used for trend test and abrupt change detection. The results show that: (1) Comfort is the main comfort level in Hunan Province, southwest and southeast Hunan are the most comfortable areas, central Hunan is the least comfortable area, May and October are the most comfortable months, July and August are the most uncomfortable hot months, January is the most uncomfortable cold month, there is few days reaching frigid level and torridity level, no broil condition occurs; (2) The human comfort index values in Hunan Province rise significantly, the days of uncomfortably cold level decrease significantly, while the days of comfortable level and uncomfortably hot level increase; (3) Comfort days of all levels change in the minimum in northwest Hunan, chances of changes from uncomfortably cold level to comfortable level and from comfortable level to uncomfortably hot level in northern Hunan and central Hunan are equal, changes from uncomfortably cold level to comfortable level are significant in southwestern and southeastern Hunan; (4) The significant increase of average human comfort index value and the significant decrease of days of uncomfortably cold level in Hunan are mutations, which occurred later in the 1990s, and became especially significant at the beginning of the 21st century.