Epidural anesthesia is often used form in Chinese primary hospitals and lidocaine is the most favorite anesthetic. Fatalities due to epidural anesthesia accident and lidocaine overdose are often happened, but there still have not obvious evidence to indicate the real reason of death according to the concentration of lidocaine in postmortem blood because the postmortem redistribution (PMR). An animal models using dogs has been developed, whereby the dogs received an intravenous, subarachnoid, and epidural injection of lidocaine (75 mg/kg body weight). The dogs were placed at room temperature after sacrifice. The cardiac blood, inferior vena cava blood, liver and cerebrum samples were collected at 0 h, 1 h, 4 h, 8 h, 24 h, 48 h and 72 h postmortem with the same animal’s corpse. The lidocaine is easier diffusion from canalisvertebralis to cardiac blood in subarachnoid administration. The level commonly has a great change from 48 h after death in cardiac blood, from 35.7 mg/L to 1421.9 mg/L, and then decreasing 50% at 72 h. The inferior vena cava blood concentration was stabilized in postmortem time. The cerebrum concentration of subarachnoid administration decreased by 50% and was observed at 72 h after death. The changes were observed in cardiac blood in intravenous and epidural administration groups, but no changes were observed in cerebrum. Lidocaine concentrations did not change significantly in the liver in any of the three groups. This study can assist toxicologists to determine which specimens should be the most appropriately during the interpretation of lidocaine concentrations in epidural accidents.