【Objective】 Using transcriptomic analysis of kernels from different periods of Elaeagnus mollis Diels. to excavate the key genes related to fatty acid synthesis. 【Methods】 We observed and recorded the fruit development of Elaeagnus mollis Diels. and used the fresh seed kernels of adult trees during the period of fruit initiation (C6), rapid fruit expansion (C7) and fruit maturity (C8) as the experimental materials, determined the fatty acid fractions and contents of the kernels of the three periods by the method of hydrolysis-extraction, and analyzed the differences in the expression of samples of the period of C6 and C7 by using transcriptome sequencing technology, and looked for the key differentially expressed genes.【Results】 The average fatty acid content of the three periods showed a gradual increase over time; 6375 up-regulated genes and 8124 down-regulated genes were obtained from the seed kernel data of the C6 and C7 periods, totaling 14 499 differentially expressed genes (DEGs). Among the selected DEGs, 8137 genes were annotated in the GO database, and 4 275 genes were annotated in the KEGG database, mainly involving metabolic pathways, biosynthesis of secondary metabolites, hormone transduction, amino acid synthesis pathways, and other pathways. Among them, pathways related to fatty acid biosynthesis and unsaturated fatty acid biosynthesis are enriched, with a focus on identifying 8 candidate genes related to fatty acid synthesis. Compared with the C6 stage, the up-regulation of EmBCCP1, EmSAD1, EmFAD2-1, EmFAD3-1, and EmPDCT1 genes, as well as the down-regulation of EmFAbG1, EmPDAT1, and EmKASI1 genes.【Conclusion】 EmBCCP1, EmSAD1, EmFAD2-1, EmFAD3-1, EmPDCT1, EmKASI1, EmFAbG1, and EmPDAT1 genes may promote the synthesis and accumulation of oleic acid and linoleic acid in the seeds of Elaeagnus mollis Diels., and serve as key candidate genes for fatty acid synthesis in Elaeagnus mollis Diels. seed kernels.