The North China Plain is one of the important grain-producing regions in China. Monitoring crop growth in this region is crucial for ensuring national food security. In recent years, high spatial-temporal resolution geostationary satellite data has been widely applied in vegetation canopy photosynthesis research, providing technical support for high-precision monitoring of crop photosynthesis. Utilizing data from the Japanese Himawari-8 geostationary satellite to retrieve the near-infrared reflectance (NIRv) and photosynthetically active radiation (PAR) for vegetation. The product of NIRv and PAR, NIRvP, is used to estimate the gross primary productivity (GPP) of vegetation. Based on the estimated GPP and flux data of winter wheat in the North China Plain area from January to July 2018, this study investigates the differences and influencing factors of diurnal variations in GPP of winter wheat during the growing season. The results indicate that: (1) NIRvP can effectively characterize the dynamic changes of winter wheat GPP in the North China Plain, showing strong correlations at half-hourly (R²=0.75), daily (R²=0.83), and monthly (R²=0.97) scales, both NIRvP and estimated GPP values(GPPe) capture the trend of GPP's diurnal centroid shifting from afternoon to morning; (2) The effect of PAR on GPP variation influences NIRvP's ability to characterize GPP changes. When PAR is the dominant factor of GPP variation, NIRvP shows a strong correlation with GPP; (3) Seasonally, vapor pressure deficit (VPD) and land surface temperature show significant negative correlations with GPP during the growth period, whereas air temperature and PAR exhibit significant positive correlations. The contribution rates of environmental factors to seasonal GPP variations are ranked as: temperature > VPD > PAR. On a daily scale, PAR and temperature are the main drivers of diurnal GPP variations, while VPD plays the dominant role at the hourly scale. In conclusion, geostationary satellite data can be utilized for large-scale monitoring of the diurnal cycle of winter wheat GPP in the North China Plain. In the future, the utilization of high spatial-temporal resolution satellite remote sensing data could provide a theoretical basis for policy-making aimed at the sustainable development of agricultural fields in the North China Plain.