In order to reveal the relationships between seed chemical compositions and climatic factors, seven Quercus species from eight core distribution areas were selected in temperate zone of North-South Transect of Eastern China (NSTEC). The relationships between climatic factors and seed chemical compositions of the Quercus species, including starch, protein, lipid, soluble total sugars, tannin and proline were discussed. The results shown that temperature was the most important factor affected the compositions of the seeds and the annual sunlight taken the second place, while the precipitation had no significant effect on compositions of the seeds. In temperate zone of NSTEC, with increasing of latitude, the temperature decrease, the mean annual sunlight increase, and length of growing season of the trees become shorter and shorter due to the decrease of the growing degree day; starch content of Quercus seeds decreased, and tended to hydrolyze to soluble sugar. From the south to the north, the species had to improve the cold resistance of their seeds by increasing the content of total soluble sugar, protein and proline for adapting the environment of lower temperature. Moreover, there were positive relationships among the content of total soluble sugar, protein and amino acid praline of the seeds, and all of them had negative relations to starch. It is one kind of ecological strategies for the plants to adapt their living environment.