Objective To investigate the relationship between the facet angle (FA) and facet violation in percutaneous pedicle screw placement in lumbar vertebrae.Methods From December 2013 to November 2016,atotal of 115 lumbar fracture or degenerative disease patients who had undertaken percutaneous pedicle screw operation was retrospectively analyzed.There were 56 males and 59 females,with an average age of 53.71±12.19 years (ranged from 15 to 77 years).Measure the FA at the level of pedicle through CT scan,diagnosis and evaluate the grade of facet joint violation after the operation.Analyzed the effect of variant FA and lumbar segment (L-L5) on the facet violation (FV) with two-way analysis of variance,and evaluate the correlation between the FA and FV in percutaneous pedicle screw placement.Results There was no significant difference between the two groups on age,gender,and body mass index.476 percutaneous pedicle screws were operated in this study:L1 144 screws,L2 136 screws,L3 64 screws,L,72 screws and L5 60 screws.The total FV rate was 30.46％ (145/476).344 screws in the upper lumbar group,and the FV rate was 28.78％ (99/344);132 screws in lower lumbar group,and the FV rate was 34.85％ (46/132).There was no significant difference of FV rate between the two groups (x2=1.66,P=0.20).The result of two-way analysis of variance indicated that the FV rate increased dramatically when FA ＞ 35° (F=20.12,P ＜ 0.001),but FV rate was not related to the lumbar segment statistically (F=0.93,P=0.45).Spearman rank correlation analysis was performed between FA and FV rate,FV grade.The result was both positive (r=0.25,P ＜ 0.001 and r=0.27,P ＜ 0.001).Conclusion The traditional C-arm fluoroscopy percutaneous pedicle screw placement technique has a high rate of FV,and the size of FA significantly affects the incidence and severity of FV.