The present invention relates to a novel aging-resistant aerosol generating agent and preparation method thereof. The aging-resistant aerosol generating agent in the present invention comprises oxidizer, reducer and bonding agent, wherein the oxidizer is potassium nitrate, the bonding agent is phenolic resin, and the reducer is melamine; the weight percentages of the three constituents are: potassium nitrate: 60˜80%, phenolic resin: 8˜15%, and melamine: the rest. In the preparation process, phenolic resin is dissolved in ethanol to give phenolic resin solution at concentration by 40˜50 wt %; the oxidizer and reducer are pulverized, mixed, and then the phenolic resin solution is added to the mixed powder; next, the mixture is agitated, pelletized, dried, and shaped by pressure molding. Compared to that in the prior art, the aerosol generating agent in the present invention has higher fire suppression efficiency and higher fire suppression rate, and greatly improved aging resistant performance.