Abstract: [Objective] To explorthe factors affecting plumpness of balloon dilation in percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fractures (OVCF) . [Methods] A retrospective study was done on total of 153 patients who received PKP for OVCF in our hospital from January 2018 to December 2019. According to the intraoperative balloon dilation shape, the patients were divided into the full-dilation group (the FD) and the non-full dilation group (the NFD) . Univariate comparison and binary multiple logistic regression were conducted to search the factors influencing the intraoperative balloon dilation in PKP. [Results] All patients were successfully operated on without serious complications. The intraoperative fluoroscopy confirmed that the balloon fully dilated in 103 patients, accounting for 67.32%, while not fully dilated in 50 patients, accounting for 32.68%. In term of univariate comparison, although there were no significant differences in age, gender, BMI, BMD, vertebral segment distribution, operation time, bone cement injection amount, postoperative walking time and the time to resum full- weight-bearing activity between the two groups (P>0.05) , the NFD group had significantly longer course of disease (P<0.05) , significantly higher incidence of intravertebral vaccum phenomina (IVP) (P<0.05) , significantly higher ratio of vertebral com- pression and greater local Cobb angle (P<0.05) , and significantly higher incidence of vertebral re-fracture after PKP (P<0.05) compared with the FD group. As results of binary multifactor logistic regression, the IVP (OR=74.189, P<0.05) , the greater local Cobb angle (OR= 3.438, P<0.05) , higher ratio of vertebral compression (OR=1.270, P<0.05) , and longer course of disease (OR=1.057, P<0.05) were the in- dependent risk factors for inadequate balloon dilation in PKP. [Conclusion] The IVP, large local cobb angle, severe vertebral compression and long course of disease are the factors related to the incomplete balloon dilation in PKP, which should be paid attention to. In addition, inadequate balloon dilation also increases the risk of refracture of the injured vertebrae.