Summary： Relationship between ATP changes of rabbit blood and postmortem interval （PMI） was studied. Twenty-four healthy rabbits were sacrificed and randomly divided into 3 groups with 8 rab- bits of each group. The bodies of three groups were placed in calorstat at temperature of 15℃, 25℃ and 35℃, respectively. The blood from the right ventricle was sampled through indwelling needle each 4 h until 72 h after death. ATP levels in the blood samples were measured by using ATP fluo- rescence rapid detection technique at different PMIs. Blood ATP levels slightly increased in the early stage after death and then constantly declined at all temperatures （15℃, 25℃, and 35℃）. Cubic polynomial regression equations with log[ATP] as dependent variable （y） and PMI as independent variable （x） at different temperatures and the optimal time period were established as followed： Under 15℃ and during 16-64 h after death, y=-3.027×10^-5x^3＋0.003x^2-0.096x-10.625 （Ra^2=0.992, P〈0.001）; under 25℃ and during 8-56 h after death, y=-2.921×10^-5x^3＋0.002x^2- 0.059x-11.186 （Ra^2=0.989, P〈0.001）; under 35℃ and during 4-36 h after death, y=-9.769×10^-5x^3＋ 0.005x^2 -0.117x-11.166 （Ra^2=0.991, P〈0.001）. The changes in ATP levels in blood collected from right ven- tricle of rabbit cadavers showed relatively stable and regular degradation within 72 h after death at different temperatures.
