To compare the treatment efficacy of thermal ablation versus surgical resection of metachronous colorectal liver metastasis (CRLM) and to explore the potential candidates suited for thermal ablation.The data of 319 patients with CRLM who underwent radical treatment at the Cancer Hospital, Chinese Academy of Medical Sciences between November 2007 and January 2021 were retrospectively collected. The patients were divided into two groups, the thermal ablation group and the surgical resection group, according to the actual treatments they received. Propensity score matching (PSM) was applied to balance the baseline characteristics between the two groups. Cox regression analysis was conducted to identify the risk factors for recurrence and survival. Survival analysis was performed for intergroup comparison.Using PSM at 1∶1 ratio, 92 patients were included in the thermal ablation group and 92 patients were included in the surgical resection group.The median overall survival (OS) in the thermal ablation group was 49 (95% confidence interval, 37-76) months, which was shorter than that of the surgical resection group ( P<0.01). Multivariate Cox regression analysis indicated that the T staging of primary tumor, number of metastatic tumor, maximum diameter of metastatic tumor, preoperative serum carcinoembryonic antigen (CEA) level, and treatment method were independent risk factors affecting OS. Compared with the surgical resection group, the thermal ablation group demonstrated higher hepatic recurrence rate (59.8% vs. 23.9%, P<0.01), shorter disease-free survival (DFS) (10 months vs. 33 months, P<0.01), and shorter length of hospital stay (7 days vs. 14 days, P<0.01). Subgroup analysis, conducted with the data of the 319 patients before PSM, showed that early recurrence patients who underwent thermal ablation or surgical resection had comparable median OS (29 months vs. 42 months, P=0.35). For the non-early recurrence patients, the median OS of the thermal ablation group was shorter than that of the surgical resection group ( P<0.01).For the treatment of CRLM, the efficacy of surgical resection was better than that of thermal ablation. However, the efficacy was comparable between the two treatments for early recurrence patients of CRLM.Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).