The invention discloses an assembly transformer substation using a modular base. The assembly transformer substation comprises a roof and stand columns for supporting the roof, wherein a fixed structure fixedly connected with the foundation is arranged at the lower end of each stand column; the modular base is integrated with transformer substation switching equipment and a control cubicle; and wires in the control cubicle are prefabricated in a factory. Compared with the prior art, the assembly transformer substation using the modular base has the advantages that the stand columns are directly arranged on the foundation, while assembly of the transformer substation is completed, the modular base can be assembled in the transformer substation, secondary cable laying operation can be carried out on the modular base, and assembly of the transformer substation and cable laying can be carried at the same time, so that the construction cycle for constructing the transformer substation can be shortened.