Abstract: A triazine phenylimide diol monomer is prepared. The triazine phenylimide diol monomer, neopentyl glycol, and terephthalic acid undergo a co-esterification polymerization reaction, so as to obtain a super weather-resistant HAA-cured matte polyester resin. The super weather-resistant HAA-cured matte polyester resin is compounding with an HAA hydroxyalkyl amide curing agent, a matting agent benzoin, and a filler, so as to obtain a polyester resin powder coating. The polyester resin contains the triazine phenylimide diol monomer, which has a phenylimide ring and a triazine ring structure. Furthermore, a double-alkyl side chain is contained, and after the double-alkyl side chain is introduced into a molecular chain of the polyester, site blocking and shielding are provided to prevent water molecules from contacting polyester bonds in the molecular chain of the polyester.