In China, 110 kV and above transformer bushings typically use mineral oil-impregnated paper insulation structures. However, mineral oil poses significant environmental and safety risks due to its non-renewable nature, low flash point, and difficulty in degradation. In recent years, frequent failures of mineral oil paper bushings have threatened grid safety. This paper proposes the technical pathway for natural ester capacitor transformer bushings, testing and analyzing the material properties of natural ester insulating oil and oil-impregnated paper materials for bushings, and studying their material suitability. The structural parameters and design methods of natural ester capacitor transformer bushings are investigated, and electric field and temperature field simulation models are established. A prototype bushing was tri-al-manufactured and passed type tests, verifying its feasibility and rationality. The research results provide a significant foundation for the localization and application of natural ester capacitor transformer bushings.