Abstract: In order to reveal the main climatic factors that affect the chemical components of the flue-cured tobacco leaves in Henan, the meteorological data from 64 meteorology stations of Henan flue-cured tobacco-growing areas between 1981 and 2013 and the data of the main chemical components of the middle tobacco leaves were used in analyzing the main climatic characters and the status of chemical components of the middle tobacco leaves of Henan flue-cured tobacco-growing areas and the relationship between them. The results showed that, Henan flue-cured tobacco-growing areas had suitable temperature, sufficient sunlight, with the rainfall and heat having the same changes. The chemical component contents of flue-cured tobacco leaves in 9 cities contained reasonable and harmonious chemical constituents and were appropriate for high quality cigarette production. Stepwise regression analysis suggested that the main chemical components of the middle tobacco leaves had close relationship with meteorological factors as a whole and differed for different indexes. The results of dominant climatic factor analysis indicated that, in a certain range, the increase of day number of daily maximum temperature ≥35℃ during root elongating stage was favorable to the increase of total sugar and the ratio of total sugar to nicotine. The increase of day number of daily maximum temperature ≥35℃ during field growing period was unfavorable to the increase of the ratio of reducing sugar to total sugar. The increase of day number of daily maximum temperature ≥35℃ during fast growing stage decreased the content of potassium. The increase of day number of daily mean temperature ≥20℃ during fast growing stage decreased the content of nicotine. The increase of relative humidity during fast growing stage decreased the content of total nitrogen and raised the ratio of potassium to chlorine. The increase of maximum temperature during root elongating stage was favorable to the increase of the ratio of total nitrogen to nicotine. The increase of minimum temperature during maturing stage was unfavorable to the increase of the content of reducing sugar. The increase of day number of daily precipitation ≥0.1mm during field growing period was favorable to the decrease of the content of chlorine. As the influence degree of dominant climatic factors on the chemical components, the temperature factor was the largest with the second being the humidity factor, and the light factor being the weakest.