Abstract: In order to determine the key meteorological factors affecting the peanut quality and quantify the effect degree of the key climatic factors, using the methods of correlation analysis, path analysis and stepwise regression analysis, the paper studied the effects of meteorological factors on peanut quality based on the peanut quality data and meteorological data in growth period coming from the 18 main peanut producing provinces in China in 2008. The result showed that peanut protein content with the various meteorological factors were not reached significant levels, peanut fat content and >15℃ accumulated temperature was highly significant positive correlation, with the temperature difference between day and night was significantly negative correlation, and peanut O/L with the meteorological factors in growth period were all reached highly significant level in which was very significant positive correlation with the >15℃ accumulated temperature and rainfall in growth period, and was very significant negative correlation with sunshine hours and day and night temperature difference in growth period. The path analysis and stepwise regression analysis showed that the effects of various meteorological factors on the peanut protein content are not large, the main meteorological factor affecting the peanut fat content was the >15℃ accumulated temperature in growth period, and the main meteorological factor affecting the peanut O/L was day and night temperature difference in growth period. The relationship between the peanut fat content, O/L and its main impact factor can be described by a linear equation.