The invention relates to maleated rosin acyl imino amines epoxy hardener for powder coating and a preparation method thereof. The hardener has structural formula as follow. The maleated rosin is prepared by the Diels-Alder addition reaction of the rosin and the maleic anhydride, the maleated rosin is reacted with a series of diamine to generate maleated rosin acyl imino amine, and the maleated rosin acyl imino amine is taken as the hardener to be capable of inducing solid powdery epoxide resin to open ring and associate to generate a net structure; and the epoxide resin used for hardening comprises glycidol ethers epoxide resin, glycidyl esters epoxide resin, glycidyl amines epoxide resin and heterocyclic epoxide resin. The maleated rosin acyl imino amines epoxy hardener has abundant raw material resource, low cost and nontoxicity. The hardened coating has good heat resisting property, wherein 5% weight loss temperature is 288-325DEG C; good electrical insulating property, wherein dielectric constant is 4.2-4.9 F/m; and high bond strength, wherein the bond strength under room temperature is 156.1-190.2N.