Aim To investigate the safety and efficacy of excimer laser coronary atherectomy (ELCA) in the treatment of complex coronary artery diseases. Methods From December 2018 to January 1,5 cases of complex coronary artery lesions treated with ELCA assisted interventional therapy in the Department of Cardiology of the Affiliated Hospital of Jiangsu University were included. The success rate of ELCA, PCI and clinical success rate, PCI complications, major adverse cardiac events (MACE) during postoperative hospitalization and 6-month follow-up were observed.Results All of 6 lesions were in-stent restenosis, including 3 completely occluded lesions and 1 severely calcified lesion.The proportion of three vessel lesions was 40.0%. The success rate of ELCA, PCI and clinical success rate were 100%, and the complication of PCI was 0. Optical coherence tomography showed local intimal tears (7.00±3.46) after ELCA treatment. After PCI, both minimum lumen diameter (MLD) ((2.56±0.27) mm vs (1.47±0.37) mm, P＝0.006) and minimum lumen area (MLA)((6.48±1.16) mm² vs (2.14±0.62) mm², P＝0.005) increased significantly compared with ELCA treatment. The incidence of MACE during hospitalization was 0. Three cases of MACE occurred within 6 months, including 2 cases of angina pectoris and 1 case of myocardial infarction. Conclusion ELCA is safe and effective as an adjuvant treatment for complex coronary artery lesions during hospitalization follow-up.