The present invention provides a self-spreading and burning powder agent specially used in the forming course of centrifugal cast pipe. Its chemical components (wt%) are 30-80% of two or more kinds of ones optionally selected from oxides of SiO2, TiO2, Fe2O3, K2O and NiO and 20-70% of optional one or two kinds of reducing agents of Al, Ti and Si. Said powder agent is injected into the cavity body of the centrifugal cast pipe, burned to produce oxidation-reduction reaction to give out a large amount of heat quantity, so that it possesses good heat-insulating function to the internal wall of the centrifugal cast pipe, and can greatly prolong the coagulating time of the internal wall, and reduce the production of internal stress, at the same time it can form a wear-resisting corrosion-resisting deposition layer on the internal wall so as to raise the service life of the centrifugal cast pipe. |