Outdoor transformer substation construction method

The invention belongs to the technical field of transformer substations, and discloses an outdoor transformer substation construction method which comprises the steps that a plurality of drill rods are inserted in a construction area according to a drawing, the drill rods jointly define the outline of a foundation pit, the interior of the outline is an excavation area, the excavation area is excavated to form the foundation pit, and the lower ends of the drill rods are all lower than the pit bottom of the foundation pit; formworks are erected on the pit bottom and the inner wall of the foundation pit, concrete is poured, and a shaped foundation pit is formed; a plurality of prefabricated boxes are installed in the shaping foundation pit; the space between every two adjacent prefabricated boxes is filled with charcoal, and a charcoal layer is laid on each prefabricated box; erecting a template on the charcoal layer and pouring concrete to form a concrete layer; waterproof layers are laid on the concrete layer,