Abstract: Ice nucleation active bacteria existing in frozen soil exhibits high ice nucleating activity. However, improving the strength of high-temperature frozen soil by facilitating pore water ice phase transition using local sustainable bio-resources ice nucleation active bacteria is rarely mentioned. The model describes the effect of ice nucleation active bacteria on the strength of high-temperature frozen soil from microscopic perspective also remains unknown. Thus, the variation law of unfrozen water content, the shearing-deformation behaviour and the shear strength of frozen soil under different Pseudomonas syringae concentrations, soil temperatures and normal stresses are obtained by carrying out nuclear magnetic resonance and direct shear tests. The constitutive model of high-temperature frozen soil considering the effect of P. syringae is established by introducing the breakage parameters and the volume strain rate. Results show that P. syringae causes a decrease in unfrozen water content by 17.09% ~ 41.36%. The shear strength enhancement is due to the increased ice crystals at different soil temperatures. At −1℃, the cohesion increases by 58.44% ~ 112.99%, correspondingly, the shear strength increases by 9.09% ~ 64%. At −0.1℃ and −0.5℃, the shear strength increases by 0.99% ~ 33.96% due to the internal friction angle increased by 18.42% ~ 47.85%. High normal stress undermines the enhancement effect of P. syringae on the strength of high-temperature frozen soil. The constitutive model describes the deformation properties of high-temperature frozen soil affected by P. syringae from microscopic perspective, and provides theoretical basis for numerical simulations of the load-bearing capacity and safety evaluation of high-temperature frozen soil with ice nucleation active bacteria.