With the development of prefabricated steel structure box-type house construction technology, as well as the upgrading of power supply and distribution system equipment, the structural type of substation has gradually developed from reinforced concrete structure to a diversified one, the steel structure substation also gradually transited from the early traditional box-type to the modular prefabricated substation (E-house).Through the study of the actual application of E-house in the harbor project, it is concluded that the traditional box-type substation has some obvious limitations, such as narrow internal space, which cannot fully meet the space required for equipment operation and maintenance, and the internal wiring form is relatively simple, which leads to the limitation of the transformer capacity.E-house has obvious advantages in customer customization, saving on-site installation and commissioning costs, shortening project construction cycle and so on.It is more suitable for port projects with harsh geographical conditions, limited on-site staffing and tight construction period.