Abstract: The purpose of this paper is to study a kind of new ultrasonic method for hyperthermia monitoring. It is a noninvasive method based on ultrasonic tissue characterization of B-mode.The experiments were carried out on in-vitro animal tissues that were heated by hot water and microwave coagulation,and a series of B-mode ultrasonic images of liver were obtained over the temperature.Then the images were processed to extract some character parameters at different temperatures,and the temperature correlations of these ultrasonic tissue character parameters were calculated.It has been found that some parameters varied in accordance with the temperature changes in the heated tissues,and the average gray value in B-mode ultrasonic images of the heated liver has linear relation with the temperature.Experiment results show that this noninvasive technique is feasible.