Abstract: In order to investigate the response of noncoding RNA BoNR8 lncRNA transcribed by RNA polymerase III in Brassica oleracea under ABA stress and its effects on hypocotyl growth and related gene expression. In this study, it was found by bioinformatics analysis that ABA response elements existed in the upstream promoter region of BoNR8. It is predicted that it may respond to ABA stress, so the normal growth of Brassica oleracea seeds for 3 days was treated with ABA, and it was found that ABA significantly induced the expression of BoNR8 lncRNA; Subsequently, qRT-PCR was used to analyze the related functions of BoNR8 overexpressed Arabidopsis mutant. It was found that under normal conditions, the overexpression of BoNR8 lncRNA in Arabidopsis inhibited the growth of hypocotyls. Under ABA stress, the overexpression of BoNR8 lncRNA promoted hypocotyl growth and the expression of related genes EXP3 and PIN7. This indicates that BoNR8 lncRNA may regulate the growth of Arabidopsis hypocotyl by responding to ABA signals and affecting the expression of genes related to hypocotyl growth.