Objective To determine whether radiofrequency ablation using hypertonic saline solution instillation can increase the extent of thermally mediated coagulation in ex vivo pig liver tissue. Methods Fifty-six radiofrequency ablation lesions were produced in fresh ex vivo pigs liver. According to different saline solutions, the lesions were divided into six groups: 25% acetic acid, 18% NaCl, 10% NaCl, 5% NaCl, 0.9% NaCl, and distilled water. After radiofrequency ablation, the lesions size and morphology were measured and compared.Results Using different instillation, the volume of coagulation necrosis was different: 25% acetic acid >18% NaCl >10% NaCl >5% NaCl >0.9% NaCl>distilled water. Conclusion Radiofrequency ablation using hypertonic saline solution instillation can increase the volume of radiofrequency ablation induced necrosis.