Abstract: Jasmonic acid (JA) plays a significant role in the regulation of developmental processes, stress responses and secondary metabolisms in plants. Jasmonate ZIM-domain (JAZ) proteins are transcriptional repressors that regulate the process of JA signal transduction from the SCF^COI1 complex to JA response genes in the JA signaling pathway. Comparative genomic analysis was performed to investigate the original and evolutionary relationship among JAZ paralogs in plants. The main results are as follows: (1) 82 JAZ genes and their homologs were identified from 15 representative species, including the 6 major plant lineages of chlorophytes, bryophytes, pteridophytes, gymnosperms, monocots and eudicots; moreover, green algae contained no JAZ homologs, which suggests that JAZ genes probably originated from land plants. (2) Phylogenetic analysis revealed 10 well-conserved subfamilies in plants; lineage- specific expansion, especially by tandem duplication and segmental duplication among species, were the major mechanisms in the evolution of the JAZ protein family and generated several lineage-specific JAZ subfamilies in land plants. (3) Exon-intron structure analysis revealed that the gene structures of JAZ paralogs contained a variable number of introns, from 0 to 7, and variable length of introns, from 62 to 4 222 bp, which suggests the events of intron loss as well as indels within introns that contributed to the structural diversity of current JAZ homologs. We provide valuable information on research into the JAZ protein family in plants.