Objective: To compare the advantages and disadvantages of conventional ultrasound (CEUS) guided percutaneous ethanol injection in patients with residual liver cancer after radiofrequency ablation (RFA). Methods: 61 cases of primary liver cancer patients with RFA underwent percutaneous ethanol injection supplement treatment, according to the guide were divided into treatment group and control group, the treatment group using contrast-enhanced ultrasound guidance, the control group using conventional ultrasound guidance, after 1 months of treatment were ultrasonic angiography and CT evaluation. Results: 30 lesions in the treatment group, the complete destruction of the 32 lesions, the remaining active area of the 2 lesions to achieve partial inactivation. The control group of 31 lesions, the complete destruction of the 22 lesions, the focus of some of the 9 inactivation. There was statistical difference between the two groups (P < 0.05). Conclusion: the application of contrast enhanced ultrasound can effectively improve the curative effect of RFA in the treatment of liver cancer.