Taking cement-improved frozen soil as the research object, this paper, based on uniaxial unconfined compressive tests of improved-frozen soil under the conditions of different cement contents (6%, 12%, 18%) and curing ages (7 d, 14 d, 28 d), analyzed the results and probed the relationship between the strength and elastic modulus of cement-improved frozen soil and cement content and curing age. In combination with laboratory test results, numerical simulations were set with the PFC^3D group, building on the samples with 6% and 18% cement content at 14 days of curing, respectively, and the mesoscopic parameter values of the two different amounts were calibrated, which proved the simulation of cement with PFC^3D reliable to improve frozen soil, and from the microscopic view, the crack development, stress field, and the particle displacement field of the two samples were analyzed. The result shows that the force is not evenly distributed in the samples; with the main force chain on the cement particles, an increase in particles can lessen the cracks, and the failure of the 6% sample is a tensile plastic failure and that of the 18% sample is a tensile shear failure.