THE seasonal variance of soil CO_2 concentration with depth in soil profile was widely studied. Few similarresearches on this topic have been done in karst area which comprises 15% global terrestrial area. In thisnote, the research results about the seasonal and daily soil CO_2 concentration variance in karst area arereported. The soil gases were collected respectively by the sampling device at 200, 5,0, -5, -10,-15, -25, -35 and -45 cm from the land surface in meadow soil profile described by Zheng andlocated in the Hongfeng lake area in the central Guizhou Plateau which lies in the central East-Asia karstarea. Sampling time is in the morning, midday and at night in April, August and November, 1998 aswell as in January, 1999, respectively. Concentrations (volume percent) of CO_2 in soil gas samples were THE seasonal variance of soil CO_2 concentration with depth in soil profile was widely studied. Few similarresearches on this topic have been done in karst area which comprise 15% global terrestrial area. In thisnote, the research results about the seasonal and soil soil CO_2 concentration variance in karst area arereported. The soil gases were collected by the sampling device at 200, 5,0, -5, -10, -15, -25, -35 and -45 cm from the land surface in the meadow soil profile described by Zheng andlocated in the Hongfeng lake area in the central Guizhou Plateau which lies in the central East-Asia karstarea. Sampling time is in the morning, midday and at night in April, August and November, 1998 aswell as January, 1999, respectively. Concentrations (volume percent) of CO_2 in soil gas samples were