To identify the function of theSpsNAC042gene and its response to salt and drought stress, theSpsNAC042gene was transformed intoPopulus hopeiensisby the Agrobacterium-mediated leaf disc method, and the phenotypic, physiological changes and related genes expression of transgenic lines were analyzed. The results showed that the number and length of roots of transgenic lines increased significantly. The leaves of transgenic lines curled inward. Under salt and simulated drought stress, the transgenic lines showed improved tolerance to salt and drought. The activities of SOD, POD, CAT and proline content in the transgenic lines were significantly increased, and the reduction rates of total chlorophyll and MDA content were significantly decreased, which indicated that the transgenic lines showed strong physiological responses under stress. Meanwhile, the gene expression ofMPK6,SOS1,HKT1andP5CS1were significantly upregulated, and the gene expression ofPRODH1was significantly downregulated, which preliminarily verified the stress regulation mechanism thatSpsNAC042might activate. The above results showed that theSpsNAC042gene could promote root development, make leaf morphology curl, and enhanceP. hopeiensistolerance to stress.