The ±800 kV UHVDC wall bushing is an important device in the ±800 kV UHVDC transmission project in China. It is urgent to simulate and analyze the three-dimensional electric field of its key parts by using finite element numerical calculation technology to determine the rationality of traditional structure design and provide optimization scheme. In this paper

the structural characteristics and insulation properties of UHVDC wall bushing are discussed under two technical routes of epoxy impregnated paper capacitive and metal shielding. Moreover

the three-dimensional electric field distribution of metal shielding wall bushing structure is simulated by finite element method. The electric field distribution characteristics of metal shielding surface and its related accessories are analyzed. The three-dimensional solid model electric fields of the middle connection structure of the bushing and the actual size of the supporting insulator are further analyzed

and the structural type and size of the supporting insulator are optimized. For the metal shielding core structure

the high field strength area is concentrated in the metal shielding flanging position and the surface of the external grading ring. Under the double-layer metal shielding condenser structure

the surface potential and electric field distribution of the wall bushing composite insulator are relatively uniform

which can realize the compact structure design of the bushing. The research results can provide theoretical basis for the design

development and operation of UHVDC wall bushing.