15 rats were used in this experiment. After rats were killed, cells of liver were collected, smeared, fixed with Formalin in every hour within the first 24 hours then stained with Feulgen's method, With an auto-TV-image system, mean and integral optical density and abnormal index of cell DNA were measured and analyzed statistically. The results showed that the DNA degeneration rate of liver cells had a linear relationship to early postmortem period in rats.