Soil respiration is the process of soil releasing CO_2 . It is important to explore the dynamics of soil CO_2 and its controls for mechanistic understanding of the terrestrial carbon budget and global climate change. Using infrared sensors (Vaisala GMP252) and an automatic device, we monitored CO_2 concentration and apparent respiration rate (i.e.,soil surface CO_2 flux) of a limestone soil profile with high frequency,aiming to capture the diurnal dynamics of soil CO_2 and its relationship with soil temperature,soil moisture and intense rainfall during summar. The results showed that the diurnal dynamics of soil CO_2 concentration generally exhibited single-peak curves,with a maximum during 12: 00 - 13: 00 each day. Moreover,soil CO_2 concentration showed a V-shaped response to intense rainfall. Soil CO_2 had a positive correlation with soil temperature, but had a negative correlation with soil moisture. The equilibrium of HCO_3~-,CO_3~(2-) and CO_2 in the water filling in soil pore-space during rainfall may have impacts on the CO_2 concentration dynamics in limestone soil due to its alkaline property. The apparent soil respiration rate had a similar diurnal variation trend as soil temperature and CO_2 concentration,showing significant correlation with temperature,while the poor correlation with soil CO_2 concentration. Soil temperature and moisture explained 45% of the variation of apparent soil respiration rate. Our results indicated that with the impacts of intense rainfall events,short-term apparent soil respiration of limestone was mainly controlled by CO_2 exchange between soil and atmosphere,which was largely dependent on environmental factors such as rainfall,soil temperature and moisture.