Objective To investigate the effect of percutaneous endoscopic transforaminal discectomy(PETD)on L5-S1 lumbar disc herniation(LDH)and the influence of iliac crest height on the clinical efficacy.Methods A total of 86 patients treated with PETD for LDH(L5-S1 segment)from February 2019 to February 2018 were selected and grouped according to the relationship between the highest point of the iliac crest and the position of the L4-5 pedicle.Forty-eighty patients with the highest point of the iliac crest located below the upper edge of the L5 pedicle were included in group A;thirty-three patients with the highest point of the iliac crest located between the lower edge of the L4 pedicle and the upper edge of the L5 pedicle were included in group B,and five patients with the highest point of the iliac crest located above the lower edge of the L4 pedicle were included in group C.The operation indexes of the three groups were compared.The visual analogue score(VAS)and Oswestry Disability index(ODI)before and after surgery[preoperative(T0),1 week after surgery(T1),1 month,6 months and 12 months after surgery(T2,T3,T4)]were compared among the three groups.Results There was no difference in operation time and blood loss among the three groups(P>0.05).At T0,there was no difference in VAS score and ODI among the three groups(P>0.05).At T1-T4,when VAS score and ODI of the three groups were lower than that at T0,VAS in group A and B was lower than that in group C(P<0.05),but there was no difference between group A and B(P>0.05).Conclusion PETD has significantly clinical efficacy in the treatment of L5-S1 LDH,and whether the iliac crest height is higher than the level of the lower edge of the L4 pedicle will affect its clinical efficacy.