Objective To use an elastography technology and other clinical and radiological data for assessment of liver background and analyze risk factors of complications after thermal ablation in patients with hepatocellular carcinoma. Methods Demographics, laboratory analyses, and radiological characteristics were collected from all patients. Main elastography-related indicators included F index (fibrosis index), A index (inflammation index), ATT (attenuation coefficient), E (kPa), AREA (area of blue parts), and CORR (correlation). All complications after thermal ablation were collected. Univariate analysis was performed to detect significant variables, which subsequently entered a stepwise logistic regression analysis (conditional forward selection) to identify independent variables. Results A total of 218 patients from October 2020 to June 2023 with 291 thermal ablation sessions were enrolled. 115 patients (52.8%) developed complications. Fifteen patients (6.9%) developed major complications. Minor complications included postoperative pain (20.6%), fever (19.3%), effusion (22.5%), and hyperammonemia (1.8%). AREA (P = 0.034), tumor size (P = 0.005), and abnormal aspartate aminotransferase (AST) (P = 0.018) were independent predictors for complications. F index (P = 0.021), tumor size (P < 0.001), and abnormal AST (P = 0.047) were independent predictors for effusion. The results of univariate analysis of infection showed that tumor size, CORR, ATT, diabetes, Child–Turcotte–Pugh grade, abnormal AST, total protein, and albumin were significant (all P < 0.05). Conclusion Several radiological and combinational elastography indicators related to liver fibrosis, steatosis, or inflammation were significantly correlated with the occurrence of complications. Clinical assessment of the liver background should not be neglected in the management of postablation complications.