The invention discloses a foundation of a power distribution equipment building of a prefabricated transformer substation. The foundation comprises two stubs, a grade beam and a bottom plate. Liftingplatforms are arranged on the side walls of the stubs, adjusting holes are formed in the lifting platforms, two ends of the grade beam are separately arranged on lifting platforms of the stubs, the bottom plate is arranged on the grade beam, a leveling device is arranged in each adjusting hole, reinforcing steel bars are arranged on the stubs and the grade beam, after the grade beam is arranged onthe lifting platforms, and the reinforcing steel bars on the grade beam are fixedly connected to the reinforcing steel bars on the stubs. The construction method comprises the following steps: excavating the foundation; then putting the stubs in the foundation and leveling the stubs; putting the grade beam and the bottom plate; then carrying out welding and fixing; and finally, casting concrete.The foundation has the advantages that as the upper structure and equipment of the power distribution equipment building are carried out in a standardized manner and the sizes and positions of the upper structure and an equipment load are relatively fixed, the structure and equipment foundation of the power distribution equipment building can be arranged in a standardized manner, so that convenience is brought to production of prefabricated parts on a large scale; the prefabricated foundation can lower the design and on-site production cost and is convenient to construct.