The invention discloses a preparation method of hexaaniline cyclotriphosphazene and non-halogen flame retardant epoxy resin composition. The preparation method of hexaaniline cyclotriphosphazene comprises the following steps: adding solvent, hexachlorocyclotriphosphazene, aniline and acid-binding agent into a reaction device, stirring and introducing nitrogen for protection, heating the mixture to 50-120 DEG C, adding catalyst into the reaction device, reacting for 5-16h and cooling to room temperature, filtering, carrying out reduced pressure distillation on the filtrate, carrying out evaporation to remove solvent to obtain brown thick product, placing the product in a drying oven, drying for 8h in vacuum at 40-70 DEG C, crushing to obtain powder product, namely the hexaaniline cyclotriphosphazene. The non-halogen flame retardant epoxy resin composition applied to large-scale and very-large-scale integrated circuits encapsulation is prepared by mixing the prepared hexaaniline cyclotriphosphazene with o-cresol formaldehyde epoxy resin, microsilica, curing catalyst, silane coupling agent, lubricant, flexibilizer and stearic acid, milling, crashing and demagnetizing.