Tung oil tree(Vernicia fordii) is one of the four woody oil plants in China. The current research of Tung oil tree focuses primarily on selective breeding, cross-breeding, and reconstruction of low-yield forests, but the molecular mechanisms related to fatty acid elongation of tung oil tree are still not covered. RNA-seq technology was used to compare and analysis the different expression of tung oil tree’s fatty acid elongation metabolism during three different development stages, which include fruit enlargement stage, initial stage of lipid synthesis, and peak stage of lipid synthesis . This research comprehensively analyzed the fatty acid elongation metabolism in tung oil tree’s seeds based on the nr, Swiss-Prot, KEGG and COG database. The results show that there are 37 non-redundant sequences participating in fatty acid elongation metabolism of tung oil tree’s seeds, which involve 9 kinds of main enzyme gene. Through the transcriptome data analysis, the genes regulating fatty acid elongation metabolism have different expression in tung oil tree’s seeds during three different development stages. And fatty acid elongation metabolism pathway was drawn according the results of comprehensive analysis. Meanwhile, this research revealed the mechanism of regulatory genes in fatty acid elongation metabolism pathway of tung oil tree’s seeds. These results not only provide resources and technical infrastructure for genetic improvement in tung oil tree’s fatty synthesis but also provide some scientific basis for molecular breeding of tung oil tree