Perilla is the medicinal and food homogeneous cash crop with the highest αlinolenic acid content. The seed oil contains more than 60% of αlinolenic acid. However， the molecular regulation mechanism of efficient synthesis and accumulation of αlinolenic acid is still unclear. Based on the sequencing results of perilla transcriptome， this study cloned Leafy Cotyledon 1 (Pf LEC1)， a key gene in the process of plant embryogenesis， from Perilla seed， and performed relevant bioinformatics analysis， realtime PCR and different determination of fatty acid content of seeds at different stages. (1) Sequence analysis results show that the gene coding region is 621 bp in length and can encode 206 amino acids. It belongs to the NFYB subunit family and contains the conserved functional domain B region of the HAP3 subunit. The protein was predicted online as an unstable，hydrophilic protein with no signal peptide or transmembrane region and localized to the cytoplasm. Evolutionary analysis showed that the protein sequence is closely related to Arabidopsis， Brassica napus， rice and corn. (2) Realtime quantitative PCR analysis showed that PfLEC1 gene was expressed in roots, stems, leaves, flowers and seeds, with the highest expression in seeds and the lowest expression in roots； PfLEC1 expression was higher in the early stages of seed development， and with seed development, the expression level decreased significantly. (3) Analysis of fatty acid content of perilla seeds at different stages showed that the contents of oleic acid and αlinolenic acid gradually increased with the development of the seeds， while the content of palmitic acid，stearic acid，and linoleic acid changed in reverse. It increased from 33.16% in 5 days to 65.16% in 20 days，indicating that the content of αlinolenic acid in perilla seeds accumulated rapidly with the development of seeds. It is speculated that PfLEC1 may be closely related to the highlevel synthesis and accumulation of αlinolenic acid in perilla seeds. This study lays the molecular foundation for further exploration of the function of PfLEC1 gene in the future.