Objective To evaluate the efficacy of Schizas morphological classification and dural sac area measurement in the diagnosis of lumbar spinal stenosis. Methods Eighty-four patients with low back pain were randomly selected as subjects. Schizas system and dural sac area measurement were used to grade the results of lumbar MRI. The consistency and reliability of the results between the two groups were compared. According to the clinical diagnosis results of the patients, the accuracy, sensitivity and specificity of the two grades were analyzed. Results The consistency between the two methods of Schizas system and dural sac area measurement was excellent. Both classification methods have good retest reliability. The accuracy, sensitivity and negative predictive value of Schizas system were significantly higher than those of DSCA grading system. Conclusion Schizas system and DSCA measurement are reliable grading systems, and both methods can be used to evaluate lumbar spinal stenosis. Compared with DSCA measurement, Schizas system is more efficient in clinical diagnosis.