In order to determine the contribution rate of climate resources at different growth stages of the flue-cured tobacco to its quality, we have used the basic meteorological datas and the chemical constituents of tobacco in Ankang, Shaanxi tobacco area in 2002–2011 as the material for our research, analyzed the average temperature, precipitation and sunshine hours of different growth stages of the flue-cured tobacco by means of principal component analysis method, set up the climatic comprehensive index (CCI) of different growth stages, and investigated the relationship between CCI of every growth stage and chemical comstituents of tobacco by means of correlation analysis, path analysis and decision analysis. The result shows that, on the influence of CCI on the nicotine content at different growth stages, the effect at the early maturity stage is the largest and comes from them directly, the effect at fast growing stage is the least; on the influence of CCI on the total sugar content, the effect at the late maturity stage is the largest and comes from them directly or indirectly at the fast growing stage, the effect at the early maturity stage is the least; on the influence of CCI on the sugar/nicotine proportion, the effect at the late maturity stage is the largest and comes from them directly or indirectly at the early maturity stage, the effect at the fast growing stage is the minimum.