In order to compare the clinical effect of different surgical technique of ligamentum flavum in percutaneous endoscopic interlaminar lumbar discectomy. From March 2015 to March 2019, 86 cases of L₅-S₁ lumbar disc herniation (LDH) were analyzed retrospectively. According to the different treatment of ligamentum flavum during operation, the patients were divided into control group (n=55) and modified group (n=31). The age, gender, course of disease, duration of surgery, intraoperative bleeding, hospital stay, and surgical related complications between the two groups of patients were analyzed and compared. One month, three months and six months after the operation, the routine outpatient reexamination and follow-up were carried out. Numerical rating scale(NRS) and modified macnab were used to evaluate the effect of operation. SPSS 19.0 was used to process the data. Mean±SD was used for measurement data. Comparison between groups using independent sample t-test, and analysis of variance of repeated measurement data was used for the NRS score comparison before and after operation. The counting data were expressed in percentage, Fisher exact test or χ² test were used for comparison between groups, and Mann Whitney rank sum test was used for comparison of follow-up time and grade grouping data between groups. The results show that the postoperative pain score of both groups decrease significantly(overall variance within the group F_within=197.477, P=0.001). There is no difference between the two groups (inter group overall variance value F_interg=1.701, P=0.203).The time factor has no effect on the results of the two groups(Interaction effect value F_inter=2.231, P=0.108). The NRS score of the modified group is significantly lower than that of the control group (t=2.086, P=0.046). According to modified Macnab criteria, there is no significant difference between the two groups (distribution of postoperative outcomes U=782.000, P=0.308). It is concluded that the modifiedsurgical technique of ligamentum flavum in the PEILD will not prolong the operation time or increase the amount of bleeding. While removing the herniated intervertebral disc, it can preserve the integrity of the relevant tissue structure, achieve satisfied clinical effect, and conforms to the core concept of minimally invasive surgery.