Objective To investigate the related factors of bone cement dispersion in PKP treatment of thoracolumbar osteoporotic fractures. Methods 103 patients with osteoporotic thoracolumbar compression fractures who underwent PKP operation in our hospital from March 2017 to March 2019 were selected and divided into fresh group (≤ 3W), subacute group (3-6w) and old group (> 6W) according to the time from fracture to operation; They were divided into high-dose group (> 3ml) and low-dose group (< 3ml) according to the amount of bone cement injected; According to the degree of vertebral compression, it was divided into grade I (≤ 25%), grade II (26% - 40%) and grade III (> 40%); According to the viscosity of bone cement, they were divided into high viscosity group and low viscosity group. The volume of bone cement in vertebral body was measured and the diffusion coefficient of bone cement was calculated. The effects of different bone cement injection volume, different operation time, different vertebral compression degree and bone cement viscosity on the dispersion coefficient of bone cement were compared. Results There were significant differences in the diffusion coefficient of bone cement among the groups with different injection amount of bone cement, different fracture to operation time and vertebral compression degree (P < 0.05). In the high viscosity cement group and low viscosity cement group, the dispersion coefficient of bone cement was similar, and the difference was not statistically significant (P > 0.05). With the increase of bone cement injection volume, the time from fracture to operation and vertebral compression increased, the dispersion coefficient of bone cement gradually decreased. Conclusion Different amount of bone cement injection, different fracture to operation time and vertebral compression degree can affect the dispersion of bone cement in the vertebral body after PKP. The dispersion coefficient of low viscosity bone cement is similar to that of high viscosity bone cement, but the high viscosity bone cement is mostly solid mass like dispersion distribution in the vertebral body, while the low viscosity bone cement is mostly honeycomb like, and compared with low viscosity bone cement, the leakage rate of high viscosity bone cement is lower, which has relatively good safety.