By continuous monitoring at eleven CO2 concentration sites in Furong Cave，Chongqing，China from September 2009 to November 2010，it was concluded that CO2 concentration showed obvious temporal and spatial variation characteristics. In space，because of the closed the environment，CO2 concentration generally increased from the entrance of the hole to the end of the hole. In addition，the number of tourists，the shape of tunnel and other factors had a certain impact on its. In the season，it had a certain amount of response relationship between CO2 concentration and the external environment of Furong cave.In the winter，because of the lower outside temperature and less precipitation，the CO2 concentration was also lower in the cave