In this study, we continuously observed the carbon flux during the rice growth period(June-September, 2019) in central Hunan using the eddy covariance technology, and analyzed change characteristics of the carbon exchange, including net carbon exchange amount(NEE), total primary productivity(GPP) and total breath(Reco). The results showed that the carbon flux during the growth period has obvious characteristics of diurnal and seasonal changes: the monthly average daily change of carbon flux was generally a “U”-shaped single-peak curve change, and the variation among the studied different months is reflected in the height of the "U"-shaped curve. In the medium rice field, the carbon sequestration capacity followed a weakening trend over the five stages, booting stage, full heading stage, middle filling stage, tillering stage，and mature stage. The change curves of NEE, GPP and Reco showed the features in “U”, inverted “U” and “bias” shapes respectively. The total NEE was, –173.93 g/m2, GPP 587.62 g/m2, and Reco 413.68 g/m2. The study found that the middle rice field in the central Hunan region exhibited a relatively strong carbon sink function, which was the material basis for yield formation and yield potential mining and probably presented the research future.