To investigate the impact and extent of meteorological factors on the grain filling rate and thousand-grain weight of rice, a series of staged rice planting experiments were conducted, principal component analysis (PCA) and redundancy analysis (RDA) were utilized to deeply analyze the meteorological factors. The results revealed that photothermal meteorological factors were the main factors affecting the grain filling rate of rice. Through redundancy analysis, it was showed that daily average temperature, daily maximum temperature, stage accumulated temperature, stage sunshine duration, and daily temperature range were positively correlated with the grain filling rate but negatively correlated with thousand-grain weight. Among these factors, daily maximum temperature, daily minimum temperature, and daily temperature range had the most significant impact on the grain filling rate and thousand-grain weight of rice. The research results provided some parameter data and technical support for agricultural meteorological services during key growing seasons of rice, in order to improve rice yield and quality.