Objective: This study aims to determine the biomechanical effects of different volumes of bone cement-augmented pedicle screws (CAPS) on osteoporotic patients following transforaminal lumbar interbody fusion (TLIF) under vertical WBV conditions. Methods: A nonlinear finite element (FEA) model of an osteoporotic lumbosacral spine was developed, simulating L4/5 TLIF. Based on the volume of polymethylmethacrylate (PMMA), three groups were created: control group (unilateral 0 mL), observation group 1 (unilateral 1.5 mL), and observation group 2 (unilateral 2.5 mL). A 40 N vertical sinusoidal load (5 Hz frequency) and a 400 N preload were applied to simulate physiological compression due to vertical vibration, and body weight. The dynamic response of these models under axial cyclic loading was compared across the groups. Results: Among the three groups, observation group 1 exhibited greater nucleus pulposus pressure, maximum annulus fibrosus stress, and disc bulge at adjacent segments than the control group, which in turn was greater than observation group 2. Across all three groups, the differences were not statistically significant. The maximum von Mises stress on the L4 inferior endplate and L5 superior endplate were decreasing as bone cement volume increased. This trend also appeared in the maximum von Mises stress in the bone around the pedicle screws. Conclusion: Under vertical WBV, increasing the volume of PMMA within a certain range reduces the risk of screw loosening, and Cage subsidence. But, under vertical WBV, a bone cement volume of 2.5 mL in pedicle screw augmentation exhibits the optimal biomechanical performance. These findings may help guide clinical treatment.