Objective: To analyze the efficacy and safety of modified transforaminal endoscopic system (TESSYS) in the treatment of aged degenerative lumbar spinal stenosis. Methods: Fifty-two elderly patients with degenerative lumbar spinal stenosis who came to our hospital from September 2016 to December 2017 were randomly divided into an experimental group and a control group (26 cases for each). The control group was treated with conventional TESSYS, and the experimental group patients use the modified TESSYS procedure. Patients in the two groups were compared 1 month, 3 months, and 6 months after surgery (modified Macnab efficacy scale), surgical indicators (operation time, intraoperative blood loss, and hospital stay), Oswestry Disability Index (ODI) score, and pain Visual Analogue Scale (VAS) scores and incidence of complications. Results: Two patients in the experimental group and one patient in the control group were converted from intervertebral canal decompression under foraminoscopy to conventional spinal canal decompression. There was no significant difference in efficacy between the two groups at 1 month and 3 months (Z=1.255, 0.946; P=0.209, 0.334). The efficacy of the two groups 6 months after the operation was better than those of the first month (Z=2.106, 2.096; P=0.035, 0.036). Compared with the control group, the efficacy of the experimental group was better at each time after operation (Z=2.515, 2.052, 2.519; P=0.012, 0.039, 0.012). The intraoperative blood loss and postoperative hospital stay in the experimental group were significantly lower than those in the control group (t=−4.998, −2.299; P<0.001, P=0.026). There was no statistical difference in the operation time between the two groups (t=1.609, P=0.114). There was no significant difference in preoperative ODI scores between the two groups (P>0.05). The postoperative ODI scores in the two groups were significantly lower than before surgery (P<0.05). Among them, ODI scores in the experimental group were significantly lower than those of the control group in the postoperative period (t=−2.129, −2.831, −3.245; P=0.039, 0.006, 0.002). There was no significant difference in preoperative VAS scores between the two groups (P>0.05), the postoperative VAS scores were significantly lower than before surgery (P<0.05). Compared with the control group, the VAS of the experimental group was lower than those of control group (t=−2.035, −3.289, −4.375; P=0.047, 0.002, <0.001). No deaths occurred in both groups. There was no statistical difference between the control group and the experimental group (8.33% vs 16.00%, χ²=0.146, P=0.702). Conclusion: The modified transforaminal endoscopic system is superior to conventional ones in the treatment of degenerative lumbar spinal stenosis in the elderly. It can effectively reduce intraoperative blood loss, reduce pain, and significantly improve functional status, the safety is similar to conventional surgery.