The invention relates to a gradient utilization method of animals dies of diseases. The method comprises the steps of conducting pyrogenic decomposition on the animal bodies dies of diseases or meat and bone meal obtained through pretreatment, obtaining coke, pyrolytic tar and pyrolysis gas through preparation, serving the coke absorbed with smoke pollutants as fertilizer or soil improvement agents, and achieving gradient utilization. The pyrolytic tar is used for preparing biodiesel, the pyrolysis gas is used for providing the heat needed by the pyrolytic process, the method is low in energy consumption or does not need the external energy consumption, the added value of products is high, and the method is suitable for application and popularization.