［Objective］ By regulating the molecular structure and index design of acrylicprepolymers and chemically modifying them in the synthesis of polyester resins to achieve synergisticeffects，a kind of acrylic modified polyester resin for ultra-high weather resistance powder coatings wasexplored and developed.［Methods］The effects of the composition of acrylic prepolymer monomers， the types and dosages of reactive groups，and the dosage of acrylic prepolymers on the performance ofacrylic modified polyester resins and powder coatings were studied.［Results］The modified polyesterand its powder coating prepared by adding 20% acrylic prepolymer with methyl methacrylate as thehard monomer and acrylic monomer as the reactive group with an acid value of 30 mgKOH/g during thepolyester synthesis stage，exhibit significantly improved weather resistance compared with conventionalsuper weather-resistant polyester. Moreover，key application indicators such as inclined fluidity，water boiling resistance and salt spray resistance all meet the requirements of industrial applications.［Conclusion］ Based on the above research，the optimal formula and index parameters were determined，providing the initial technical support and product solution for the industrial application ofacrylic modified polyester resin in ultra-weather-resistant powder coatings.