Background: Trees such as Populus are planted extensively for reforestation and afforestation. However, their successful establishment greatly depends upon ambient environmental conditions and their relative resistance to abiotic as well as biotic stress. Polyphenol oxidase (PPO) is a ubiquitous metalloproteinase in plants, which plays crucial roles in plant resistance against biotic and abiotic stresses. Although the whole genome sequence of populus trichocarpa has long been published, little is known about the PPO genes in Populus, especially those related to drought stress, mechanical damage, insect feeding and hormone response at the whole genome level. Results: In the recent research, a genome-wide analysis of the Poplar PPOs family was finished and 18 PtrPPOs gene were identified. Then, bioinformatics and qRT-PCR were applied to analyze the gene structure, phylogeny, chromosomal localization, gene replication, Cis-elements, expression patterns of PtrPPOs. Sequence analysis revealed that 2/3 of the PtrPPO genes not contained introns. Phylogenetic analysis revealed that all PPOs gene were split into 11 subfamilies, and woody plants differentiated a large number of PPO genes. 18 PtrPPOs gene were disproportionally apportioned on 19 chromosomes, and the number of three pairs of segmented replication genes and four tandem repeat genomes were detected in poplars. Cis-acting element analysis identified a large number elements of growth and development, secondary metabolism process, and stress-related elements on the promoters of different PPO members. Furthermore, PtrPPO genes were expressed preferably in young plant tissues and fruits. In addition, some PtrPPOs could be significantly induced by PEG, ABA and JA, thus revealing their potential role in regulating stress response. Conclusions: Comprehensive analysis is helpful to select candidate PPO genes for the follow-up study of the biological function, and molecular genetic progress of stress resistance in forest trees provides genetic resources.