Background: Lumbar facet joint is an important element of spinal “three-joint complex”. Whether there is a relationship between strange structure of facet joint and adolescent lumbar disc herniation (ALDH) is nonetheless controversial, and the current research is mainly centered on adults. Objective: To find out the normal lumbar facet joints between 13 and 18 years old to provide anatomical basis for early diagnosis and therapy of lumbar disc herniation. Methods: CT imaging information of 32 sufferers with lumbar disc herniation aged from 13 to 18 years old in Inner Mongolia have been collected as the ALDH group, and 62 wholesome subjects in the equal period had been chosen as the normal group. Uncooked records of continuous scanning lumbar tomography pix were imported into MIMICS 21.0 for evaluation and size in DICOM format. The parameters include facet joint height, facet joint width, et al. Results: 1. The left and right transverse angle of L5S1 segment in the ALDH group were (52.41 ± 9.2) ° and (55.99 ± 10.91) ° (P