Fatty acids are synthesized and stored in seeds during development in Brassica napus. Understanding the molecular mechanism behind fatty acid biosynthesis during seed development is a crucial research objective. In this study, we proved that exogenous application of abscisic acid (ABA) to the siliques can efficiently improve unsaturated fatty acid content in rapeseeds. Then we identified a total of 97 novel microRNAs (miRNAs) and 211 known miRNAs in the seeds of B. napus by high-throughput sequencing. Among them, a total of 23 differentially expressed miRNAs were observed between siliques trea...