Abstract: Carotenoid cleavage dioxygenases（CCD）specifically catalyzed the cleavage of conjugated double bonds of carotenoids to form various apocarotenoids and their derivatives,which played various important roles in plant growth and development and stress response. However,no research has been reported on PtrCCD in the woody model plant Populus trichocarpa. This study found that its expression level was significantly different under salt stress and drought stress. Based on this,it was planned to reveal the function of PtrCCD family at the molecular level.. The number of PtrCCD family members,evolutionary relationship,chromosome location,gene structure,basic characteristics of the encoded protein,promoter cis-acting elements,and response to drought and salt stress of PtrCCD gene family were analyzed at genome-level of P. trichocarpa,respectively. The results demonstrated that the PtrCCD family could be divided into two sub-families,CCD4 and CCD8,which included 9 and 2 genes,respectively. There were 5 pairs of paralogous genes,with Ka/Ks far less than 1. All proteins encoded by the PtrCCD family contained 5 common Motifs,such as Motif 1,Motif 2,Motif 3,Motif 9,and Motif 11. The promoter regions of PtrCCD gene family contained a large number of abiotic stress and hormone response cis-elements,among which the PtrCCD8 a promoter contained 5 types and 16 elements.Analysis of the expression characteristics of the PtrCCD family showed that the PtrCCD family genes exhibited tissue-specified expression patterns and mainly expressed in stems compared with in roots and leaves,respectively. Moreover,there were significant differences of expression levels of PtrCCD family genes among roots,stems,and leaves of poplar in response to drought and salt stress during different times. The PtrCCD gene family had different response to drought and salt stress,which further indicated that this gene family played an important role in abiotic stress.