Objective To study the relationship between sagittal facet joint and degenerative lumber spondylolisthesis (DLS) by observing the changes of the lumbar facet joint angle. Methods Fifty-seven patients with DLS who met the inclusion criteria between January 2013 and February 2016 were collected (DLS group). There were 26 males and 31 females, with the mean age of 54.0 years (range, 34-84 years). Forty patients without DLS at same stage were collected as control group. There were 23 males and 17 females with the mean age of 55.6 years (range, 29-82 years). There was no significant difference in gender and age between 2 groups (P>0.05). The lumbar facet joint angles were measured and compared by MRI scanning images in 2 groups. In DLS group, X-ray films were used to evaluated the degree of the lumbar spondylolisthesis on the basis of the Meyerding standard, and compared the facet joint angles between patients of different DLS degree. Results Facet joint angles in the DLS group [(34.18± 4.81)°] were significantly smaller than those in control group [(45.87±1.09)°] (t=15.073, P=0.000). In DLS group, the patients were rated as degree Ⅰ in 24 cases, degree Ⅱ in 19 cases, degree Ⅲ in 14 cases. As the degree of DLS increased, the lumbar joint angle decreased gradually, and showing significantly differences between patients of different DLS degree (P<0.05). Conclusion Sagittal lumbar facet joint may be one of the main risk factors of DLS.