Abstract: In order to explore the source of CO₂ in karst cave and the relationship between cave pCO₂ and cave environment, a constant cave monitoring study(including air temperature in and out the of cave, local precipitation, soil pCO₂, cave air pCO₂, and the relative humidity of cave air) had been carried out during 2012-2016 A.D, in Furong Cave, Chongqing, Southwest China. The results showed that ⅰ) The mean cave air temperature was stable at 16.4±0.4℃ at “Great Hall” in the deep of the cave, while the mean temperature was 19.1±1.0℃ and the changing amplitude of monthly average cave air temperature was about 5℃ at the monitoring site named “Lotus Guanyin”, approximately 150 m from the entrance. It was explained that ventilation effect was stronger near the entrance than the deep of cave. ⅱ) The air relative humidity changed from 95% to 100% at “Great Hall”. In contrast, the average relative humidity was 94% and was lower in summer and higher in winter at “Lotus Guanyin” which was in line with the seasonal variation characteristics out of the cave. ⅲ) There was a seasonal change in cave air pCO₂, with maximum cave air pCO2 values in autumn and the minimum values in winter. The peak values of cave air pCO2 were measured in October or November, lagging 1-2 months behind the peak of overlying soil pCO2. It was considered that the local meteoric precipitation and the thickness of overlying bedrock were the main factors. ⅳ) The effects of overlying soil pCO₂, cave temperature and relative humidity on pCO₂ at different areas of cave were different because the cave shape, structure and tourist activity had spatial differences. Consequently, it is important to pay attention to the cave spatial structure in the process of cave monitoring and discussing the influencing factors of cave pCO₂.