In response to the call for a“resource-saving and environment-friendly”society, as well as the construction of modernized substations, an optimized design has been proposed for the distribution units of 110 kV substations in Huangtudian, Changde. Outdoor GIS equipment, which has canceled the main transformer outlet side and the incoming line side isolation switch, has been applied in 110 kV distribution units, adopting the double outlet mode to make full use of the vertical space within the outlet space intervals. Novel gas insulated switchgear has been used in 35/10 kV distribution units. The optimized design, with its total land use 68% less than the conventional designs, helps to realize a more compact substation layout than before.