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 rabbits of each group. The bodies of three groups were placed in calorstat at temperature of 15°C, 25°C and 35°C, 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 fluorescence 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°C, 25°C, and 35°C). 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°C and during 16-64 h after death, y=-3.027×10(-5)x(3)+0.003x(2)-0.096x-10.625 (R a (2)=0.992, P<0.001); under 25°C and during 8-56 h after death, y=-2.921×10(-5)x(3)+0.002x(2)-0.059x-11.186 (R a (2)=0.989, P<0.001); under 35dgC and during 4-36 h after death, y=-9.769×10(-5)x(3)+ 0.005x(2)-0.117x-11.166 (R a (2)=0.991, P<0.001). The changes in ATP levels in blood collected from right ventricle of rabbit cadavers showed relatively stable and regular degradation within 72 h after death at different temperatures.