Abstract: In order to clarify the function of PtrWRKY51 gene of Populus trichocarpa,the CDS of PtrWRKY51 gene was cloned using P.trichocarpa from Nisqually-1 strain as material.The function of PtrWRKY51 gene was studied by bioinformatics analysis,and assayed by yeast self-activation verification,and subcellular localization and simulated drought stress by real-time qPCR.The results showed that the CDS of PtrWRKY51was 579 bp and encoded 192 aa.Bioinformatics analysis and subcellular localization experiments showed that PtrWRKY51 was a non-transmembrane alkaline unstable hydrophilic protein,located in the nucleus and contained a conserved domain unique to WRKY family,it was a WRKY transcription factor classified to class IIc The yeast self-activation verification experiment showed that PtrWRKY51 gene could self-activation activity qRT-PCR showed that the expression of this gene was significantly induced by 8% PEG6000 and reached the highest expression in stem and leaf after 12 h stress,while the roots appeared after 24 h stress.This study could provide reference for further study on stress tolerance and biological function of PtrWRKY51.