SET domain-containing gene is a highly conserved gene family with SET domain involved in the regulation of life processes in the plants. In order to investigate the SET gene family and its expression in cabbage (Brassica oleracea), the SET genes were identified by bioinformatics, and the expression patterns of these genes in different tissues were analyzed by qRT-PCR and RT-PCR. As results, a total of 28 SET domain-containing genes were identified from the cabbage genome, which were widely distributed on all chromosomes except for the first chromosome. The expected molecular weight of proteins ranged from 29.20 to 185.16 kDa, and the isoelectric point ranged from 5.02 to 9.06. The number of introns ranged from 0 to 23. Phylogenetic analysis showed that the SET domain-containing genes could be classified into seven subgroups, of which II and V subfamilies contained most members. The results of qRT-PCR revealed that seven representative SET domain-containing genes were consistently expressed in various tissues, including the roots, stems, buds and flowers, except for the leaves. The high expressions of seven genes were observed in pollens. Further study showed that the highest expression of these genes was manifested in most sporogenous cells during pollen mother cell stage. In conclusion, this study systematically investigated the structure, phylogenetic relationship and the expression pattern of SET domain-containing family genes of B. oleracea, which provides a theoretical foundation for the further functional analysis of SET domain-containing family genes in B. oleracea.