In the chemical structure of polysilazane, the electronegativity of Si-N bond is 1.2, between Si-C bond and Si-O bond, which is similar to si-cl bond, so Si-N bond has about 30% ionic bond characteristics; meanwhile, there is a coyoke between lone pair electron on nitrogen and 3D empty orbit on silicon (P-D cross cover); the energy of Si-N bond is about 360 kJ / mol, which is more than that of Si-O bond and Si CL bond In the reaction, the Si-N bond can be easily converted into other new bonds, which is very beneficial for the development of new compounds. For example, it is easy to react with many electrophilic organic substances and nucleophilic organic substances, such as epoxy resin or phenolic resin. The heat-resistant nitrogen element and heat-resistant and weather resistant Si element are introduced into the compound to enhance the heat resistance and weather resistance of the compound, which is very useful for coatings.