A microwave tissue coagulator(MTC) was inserted into a piece of swine liver with different water contents and the thermograph of tisssue was recorded by the Probeye thermal video system.A linear regressive relationship was revealed between the rise of central temperature in the tissue and microwave radiation duration. The effect in the tissue with high water content was much stronger than that with low water content (P<0.005). The penetrating radius of microwave radiation attenuated exponentially (Y=116.7e^-0.96x). As the radiation continued, the wedge-shape of tissue thermograph changed to ellipse-shape. In a controlled study on rabbit hepatic resection with MTC or cautery,the blood loss of the MTC group was lower than that of the cautery(P<0.05). No delayed liver stump bleeding and bile leakage occured in the MTC group.The histologic findings indicated a similar healing process at the resected liver stump in the two groups. Postoperative increase in activities of SGPT and AKP was transient in both groups. These findings led us to conclude that MTC could be applied safely,effectively and easily in the field of hepatic surgery.