Gross primary productivity (GPP) is an indicator that reflects the absorption of atmospheric CO2 by crops through photosynthesis and serves as an important starting point for crop yield formation. The remote sensing measured sun-induced chlorophyll fluorescence (SIF) had highly advantages in GPP estimation. However, there were few studies in estimating rice GPP using remote sensing measured SIF. The paddy field in Jiangxi Province was taken as research object, a non-linear model for estimating rice GPP was constructed based on remote sensing measured SIF and ground flux observation data, and then the GPP over paddy field in Jiangxi Province during 2001—2020 was estimated. The results showed that compared with MOD17 GPP and GOSIF GPP, the SIF-based non-linear model had higher GPP estimation accuracy. The model can better capture the seasonal variations of rice GPP in both the rice seasons and non-rice seasons, but it performed poorly during the period of early rice to late rice transition. During 2001—2020, the annual average rice GPP for the Jiangxi Province was (2082.8±143.2)g/(m2·a), and generally exhibited lower values in the north and higher values in the south. The areas with low GPP values were mainly located in the Nanchang City and its surrounding areas, while high values were found in Ganzhou City and Jingdezhen City. During 2001—2020, the rice GPP in Jiangxi Province showed an overall increasing trend with an increasing rate of 24.3g/(m2·a). The regions with the largest increasing trend were located in the southern part of the Jiangxi Province, while areas with the smallest increasing or decreasing trend mainly located in Nanchang City and Jiujiang City, possibly related to the transition of “double cropping rice to single cropping rice”. The main influencing factor for interannual variations in rice GPP in Jiangxi Province was temperature, with contribution rate ranging from 28.3% to 44.2%. Solar radiation had a negative contribution to rice GPP, the wind speed had a positive contribution to rice GPP in some regions, while precipitation and relative humidity had little impact on rice GPP. The research findings can provide a theoretical basis for estimating rice GPP, as well as for assessing the carbon sequestration capacity and yield estimation of rice under climate change in Jiangxi Province.