In this study, in order to explore the molecular mechanism of oil metabolism in Camellia sinensis seed, we used transcriptome sequencing to analysis three different stages with young, formation and mature stage of seed development of ‘Tieguanyin’ cultivar. The results indicated that: (1) in total, 30 940 581 clean reads were obtained after transcriptome sequencing and assembly, 36 951 nonredundant Unigene sequences were obtained after data assembly, among which 28 476 Unigene could be functionally annotated. 11 201 Unigene (30.3%) were annotated into GO database. 17 172 Unigene were involved in 127 metabolic pathways by KEGG analysis. (2) 14 fatty acid metabolism pathways were selected by KEGG, and with the development of seed, most genes in fatty acid metabolism pathway were downregulated. The number of upregulated genes was the most in the alphalinolenic acid metabolic pathway (17 genes), while the number of downregulated genes was the most in the glycerolipid metabolic pathway (58 genes). More genes were upregulated than downregulated in the alphalinolenic acid metabolism pathway during young fruit stage of tea seeds. (3) A total of 409 differentially expressed genes (DEGs) related to synthesizing of tea seed fatty acid were identified, which were involved in 14 lipid regulation pathways. Some of the genes in the alphalinolenic acid metabolic pathway, like PLA2G16, DAD1, pldA, FabF and FabI, were upregulated significantly, and then the expression was downregulated subsequently. (4) Seven CsFAD genes and one CsACP gene were inspected by qRTPCR and their expression levels were consistent with transcriptome data. With the development of seeds, CsFAD7 and Δ6CsFAD showed downregulated and CsFAD2, CsFAD6 and Δ7CsFAD showed upregulated. CsFAD8, Δ8CsFAD and CsACP showed upregulated from young fruit stage to formation stage，and downregulated from formation stage to mature stage.