Addressing the lightning protection and icing flashover issues in ± 500 kV transmission lines, this paper proposes a ± 500 kV lightning protection and icing composite insulator designed to serve both as an insulation support and for lightning protection and icing functions. Employing the finite element method, the paper conducts three-dimensional simulation calculations of the electric field of the ± 500 kV lightning protection and icing composite insulator, followed by an analysis of the distribution of electric potential and electric field intensity. Through simulation and optimized design, a hierarchical ring configuration scheme is proposed, meeting the requirements for electric field control. The results indicate a significant improvement in the electric field distribution of critical components in the composite insulator by strategically placing the runway ring and small ring on the conductor side of the insulation section, and positioning the runway ring between the lightning protection side and the insulation side. Notably, the field strength observed on the surfaces of the silicone rubber shed, runway torus, and small grading ring complies with the specified requirements for field strength control.