Prunus mume Siebold & Zucc.， known for its numerous varieties and diverse floral scents， includes cinnamyl alcohol and cinnamyl acetate as unique floral scent components in pink varieties. In plants， cinnamaldehyde is reduced to cinnamyl alcohol under the catalytic action of cinnamyl alcohol dehydrogenase （CAD）， which in turn forms cinnamyl acetate under the catalysis of acetyltransferase. Therefore， cinnamyl alcohol is not only a significant floral scent component in P. mume， but also a crucial precursor for the synthesis of cinnamyl acetate. This study identified 56 PmCAD homologous genes based on the updated genome of P. mume. These PmCAD family members can be categorized into five subgroups. The protein conserved motif composition of subgroups I， II， and III is relatively similar， with significant differences from subgroups IV and V， suggesting potential functional divergence. Chromosome segmental duplication and tandem duplication were identified as two forms of PmCAD replication in genome evolution. The promoters of PmCAD genes were found to extensively contain abscisic acid， methyl jasmonate， salicylic acid responsive elements， and meristem related elements， suggesting that PmCAD genes are mainly involved in the growth， development， and stress response. Phylogenetic analysis of CAD from P. mume and other species indicated that the three PmCAD genes located in subgroup III may be involved in floral scent synthesis. Heat map analysis in different tissues and organs indicated that the three PmCAD were all expressed in flowers. Furthermore， analysis of relative gene expression revealed that the expression patterns of the three candidate PmCAD genes varied at different stages of flowering， with higher expression levels after the flowers bloom. The in vitro enzyme activity analysis confirmed that all three PmCAD possess cinnamyl alcohol dehydrogenase activity， indicating that they jointly participate in the synthesis of cinnamyl alcohol. Subcellular localization analysis revealed differences in their intracellular distribution， suggesting distinct cellular roles. This study sheds light on the evolution and functional differentiation of the PmCAD genes in P. mume， laying a theoretical foundation for the synthesis of key floral scent components and providing theoretical bases for floral fragrance molecular breeding in P. mume.