Background: In the anesthesia management of percutaneous liver tumor ablation, the requirement of analgesia is very strict. Currently, intravenous anesthesia is commonly used, such as remifentanil combined with sedative drugs. However, the pain relief is not instantaneous after increasing the dosage of remifentanil.Esketamine, a medium-or long-term analgesic drug, does not inhibit respiration to maintain patient comfort during the ablation and reduces the consumption of remifentanil. Therefore, this experiment was designed to investigate the potential of combinational therapy and the most appropriate dose of esketamine.Methods: A total of 120 patients were randomly divided into three groups by SPSS. The regular anesthesia model included dexmedetomidine 0.5 μg/kg, intravenous glucose tolerance test, remifentanil continuous infusion, flurbiprofen 50 mg, i.v., palonosetron 0.225 mg, i.v., and 1% lidocaine for local anesthesia. Group A was the regular control group, only using the regular model; Group B also received with 0.1 mg/kg esketamine, i.v.; and Group C also received 0.2 mg/kg esketamine, i.v.. The whole experiment was doubleblind.