Objective To study the results of in situ microwave thermocoagulation therapy for liver neoplasms. Methods Thirty-one patients (male 28, female 3) with liver neoplasms underwent in situ microwave thermocoagulation therapy in recent 4 years were studied. The time of the therapy arranged from 2 to 6 minutes with the core temperature from 110℃ to 125℃. Twenty six of the thirty one (83.9%) were followed up. Results Ninty point three percent of these patients have a good result. The average survival time after the operation was 19.7 months. One-year and three-year survival rate were 77.4% and 38.7%, respectively. Conclusion The in situ microwave thermocoagulation therapy have the advantages of causing slight trauma, promoting repair, good tolerance and curative effectiveness. It’s a simple, safe and effective method with less adverse effect for treating the liver neoplasms, especially for unresectable neoplasms.