In this study, we used bioinformatics methods to identify the RPD3/HDA1 gene family in Brassica napus, and detected the expression level of this family gene in ‘Qianyouzao 2’ and ‘Zhongshuang 11’, and the gene expression characteristics of the family in two varieties under low temperature (4 ℃) and ABA stress, in order to explore the potential function of RPD3/HDA1 genes in Brassica napus, and provide theoretical basis and candidate genes for genetic improvement of stress resistance in early maturing rapeseed. The results showed that: (1) A total of 28 RPD3/HDA1 genes were identified in the whole genome of Brassica napus, and they were named BnHDA1-BnHDA28 with clustering into 4 subfamilies, the gene structures of members of the same subfamily were relatively similar, and a total of 16 pairs of replicated genes were detected in this gene family, all of them were fragment repeats. (2) A total of 675 cis-acting elements were found to be related to plant hormones, environmental stress, and light response. (3) qRT-PCR analysis showed that the expression of RPD3/HDA1 genes in ‘Qianyouzao 2’ was higher than that in ‘Zhongshuang 11’. Under low temperature stress, the RPD3/HDA1 genes in ‘Qianyouzao 2’ and ‘Zhongshuang 11’ showed differential expression, and compared with ‘Zhongshuang 11’, the down-regulation of RPD3/HDA1 genes in ‘Qianyouzao 2’ was greater. After ABA treatment, the expression pattern of RPD3/HDA1 genes in the two varieties was inconsistent, and the expression level of most RPD3/HDA1 genes in ‘Qianyouzao 2’ was lower than that in ‘Zhongshuang 11’. Research suggested that RPD3/HDA1 genes may play a regulatory role in rape flowering, and may participate in the regulation of rape growth and development and defense response through hormone signaling pathway and defense signaling pathway.