Objective To analyze the clinical efficacy of microwave ablation in the colorectal cancer with simultaneously multiple liver metastases that was initially evaluated as potentially resectable. Methods The patients with potentially resectable colorectal cancer with simultaneous multiple liver metastases treated in the Department of General Surgery of the First Affiliated Hospital of Hebei North University,the Center of Minimally Invasive Therapy in Oncology of Traditional Chinese and Western Medicine in Dongzhimen Hospital of Beijing University of Chinese Medicine,and the Second Department of General Surgery in the Fourth Hospital of Hebei Medical University from October 1,2018 to October 1,2020 were selected in this study.The general data,pathological features,treatment methods,and clinical efficacy of the patients were collected.According to the treatment methods,the patients were assigned into a surgical resection group(conversion therapy+laparoscopic primary resection+hepatectomy)and a microwave ablation group(conversion therapy+laparoscopic primary resection+microwave ablation).The surgical indicators(operation duration,time to first postoperative anal exhaust,hospital stay,etc.)and postoperative complications(anastomotic stenosis,anastomotic hemorrhage,incision infection,etc.)were compared between the two groups.The survival period was followed up,including the overall survival period and disease-free survival period,and the survival curves were drawn to analyze the clinical efficacy of the two treatment regimens. Results A total of 198 patients with potentially resectable colorectal cancer with simultaneous multiple liver metastases were included in this study.Sixty-six patients were cured by neoadjuvant chemotherapy(FOLFOX or FOLFIRI),including 30 patients in the surgical resection group and 36 patients in the microwave ablation group(with 57 tumors ablated).After the first ablation,54(94.74%)tumors achieved complete ablation,and all of them reached no evidence of disease status after re-ablation.The microwave ablation group had shorter operation duration,less intraoperative blood loss,shorter time to first postoperative anal exhaust,shorter time of taking a liquid diet,shorter hospital stay,and lower hospitalization cost than the surgical resection group(all P<0.001).In addition,the microwave ablation group had lower visual analogue scale score(P<0.001)than the surgical resection group.The incidences of complications such as incision infection(P=0.740),anastomotic fistula(P=1.000),and anastomotic stenosis(P=1.000),the overall survival period(P=0.191),and the disease-free survival period(P=0.934)showed no significant differences between the two groups. Conclusions For patients with colorectal cancer with simultaneous multiple liver metastases initially assessed as potentially resectable,laparoscopic primary resection+surgical resection/microwave ablation after conversion therapy was safe,effective,and had similar survival outcomes.Microwave ablation outperformed surgical resection in postoperative recovery,economy,and tolerability,being worthy of clinical promotion.