【Objective】 To investigate the early clinical efficacy of full endoscopic lumbar interbody fusion in the treatment of lumbar degenerative diseases with lumbar instability. 【Methods】 We made a retrospective analysis of 22 cases of lumbar degenerative diseases with lumbar instability treated by full endoscopic lumbar interbody fusion in Department of Orthopedics， Tangdu Hospital of Air Force Military Medical University from January 2019 to June 2020. The operation time， intraoperative bleeding volume， and hospital stay were recorded. The Visual Analogue Scale （VAS） for lower back pain and leg pain and Oswestry disability index （ODI） were compared before operation， 1 week， 1 month， 3 months， 6 months and at the last follow-up after operation. Modified MacNab was used to evaluate the clinical efficacy at the last follow-up. 【Results】 Operations on the 22 patients were all completed successfully. The average operation time was （206.59±5.69） min （with the range of 180-240 min）； the average volume of intraoperative bleeding was （92.73±22.29） mL （with the range of 50-120 mL）； the average hospitalization time was （8.82±1.53） d （with the range of 7-13 d）. All the patients were followed up for an average of （10.95±3.34） months （with the range of 6-18 months）. The VAS score and ODI at each time point after surgery were significantly decreased compared with those before operation （P<0.05）. The modified MacNab used to evaluate the clinical efficacy at the last follow-up showed that the total excellent and good rate was 90.91%， including 17 cases of excellence， 3 cases of good， and 2 cases of fair. 【Conclusion】 The early clinical effect of full endoscopic lumbar interbody fusion in the treatment of lumbar degenerative diseases with lumbar instability is satisfactory.