Objective To investigate the application of lower limb electromyography in guiding preoperative localization for multiple segment intervertebral disc herniation treated with ozone injection and in predicting the curative efficacy.Methods A total of 51 patients with MRI-proved multiple segment lumbar intervertebral disc herniation,who were admitted to authors' hospital during the period from January 2012 to December 2013 and who had complete clinical materials,were included in this study.Guided by DSA,intradiscal injection of ozone together with the injection of ozone plus compound betamethasone and bupivacaine into the space around the spinal nerve was carried out in all patients.The degree of lower lumbago was evaluated with M-JOA score,and Oswestry disability index (ODI) was adopted to assess the curative effect.Results Preoperative electromyography showed that 43 patients had nerve root injury,the positive rate was 84.3％.The positive HIZ sign was detected in 30 patients,with the positive rate being 58.8％.The positive Modic sign was observed in 24 patients,the positive rate was 47.1％.Postoperative MJOA scores indicated that one-,3-and 6-month effective rates were 90.1％,86.2％ and 78.5％ respectively;and postoperative ODI values showed that one-,3-and 6-month effective rates were 87.3％,79.5％ and 74.6％ respectively.Conclusion In treating multiple segment intervertebral disc hemiation with ozone injection,lower limb electromyography is very valuable in accurately making preoperative localization as well as in precisely predicting the curative efficacy,thus this technique is worth popularizing in clinical practice.