Objective To study the mechanism of myocardial dielectric property changes in radio frequency during hypothermic preservation and explore myocardial viability evaluative method. Methods Hybrid young pigs (20-30 kg) were used in the experiment. Heart arrest was induced with GIK solution. According to preservative temperature, the animals were divided into three groups: group A (4 ℃),group B (15 ℃) and group C (25 C). The heart was preserved in saline for 12,6 and 4 h respectively. Myocardial dielectric properties and ATP content were tested every 5 and 30 min during hypothermic preservation respectively. The relationship between tanoδm and ATP content was analyzed. Results Tanδm of three groups was decreased significantly at the beginning, most slightly in group A and most obviously in group C. There was no significant difference in Tanδm between group B and group C with group A at 1 h,but there was obvious difference at 2,3 and 4 h (P＜0. 05,P＜0. 05,P＜0. 01 ). There was correlation between tanδm and ATP in the three groups. Conclusion Tanδm in three groups is dropped with preservation time and temperature, and tanδm had a correlation with ATP content. Detection of myocardial dielectric property in radio frequency is a kind of quick, accurate and noninvasive method.