Abstract: In order to establish the high efficiency genetic transformation system of Populus tomentosa Carr. by Agrobacterium tumefaciens, and to obtain mass-produced transgenic P. tomentosa with MdSPDS1 gene, several key factors of P. tomentosa transferring system were optimized during MdSPDS1 transformation. The optimized conditions for transformation of P. tomentosa were obtained as follows: the explant was pre-cultivated for 3 days and infected with Agrobacterium at the concentration of OD600=0.4 for about 7 min, the foliages were co-cultured with Agrobacterium for 3 days, and the prophase and anaphase selecting methods were applied under the selection pressure of 20 and 50 mg/L Kan, respectively. Consequently, 9 out of 43(20.9%) Kan-resistant plantlets were positive by PCR identification, suggesting that MdSPDS1 gene had been integrated into P. tomentosa genome. And the transformation frequency was increased to 9.38%. Our work laid a foundation for appraisal of gene function and the analysis of salt-tolerant capability of transgenic plants in the future.