To explore the regulation of oleic acid quality formation of oil sunflower, the high oleic acid material NY7 and the low oleic acid material N96 were used as the research materials. The seeds were sampled at 7, 14, 21, 25,28, 31, 35 and 42 days after flowering, respectively. The 100-seed weight and oleic acid content of seeds at different growth stages were measured. Additionally, RNA-Seq technology was employed to conduct the transcriptome sequence of the seeds at 21, 25, and 31 days after flowering. The results showed that both high and low oleic acid sunflower seeds basically completed dry matter accumulation 21 days after flowering. In low oleic acid seeds, the degradation of oleic acid commenced after 14 days of flowering, leading to a gradual decrease in its content. Transcriptome sequencing obtained 8 955, 7 664, and 9 287 differentially expressed genes, respectively. KEGG enrichment analysis was conducted on differential genes, which were enriched in 33, 16 and 32 metabolic pathways, among which the pathway related to oleic acid formation was fatty acid degradation metabolic pathway. Within this pathway, 8 candidate genes potentially involved in oleic acid formation were identified.