According to the fact that 220 kV outgoing lines were overhead in most of 500 kV substation, some improvement measures were implemented for the 220 kV hybrid gas insulated switchgear (HGIS) distribution device in 500 kV intelligent substation, such as the configuration integration for interval equipment, the optimization design for layout and framework. The layout optimization scheme included: the configuration integration and optimization for interval equipment, the design of large span bus beam and united framework, partial double outgoing line within single bay, and so on. Compared with the 500-B-4 universal design, this optimization scheme has advantages of saving 34.1% occupied area and 28.6% structure steel consumption with same equipment investment.