The invention discloses a base plate type waterproof battery box. The battery box comprises a hollow box body and a box cover for sealing an opening, wherein the opening is formed in the upper surface of the box body, a battery pack is arranged in the box body, and a connector connected with the battery pack is arranged on the box body or the battery cover. The battery box is characterized in that the box cover and the box body are connected in a waterproof sealing manner, the connector is connected with the box body or the box cover in a waterproof sealing manner. The base plate type waterproof battery box solves the various problems of unsafety as an electric vehicle enters water, and the base plate type electric vehicle battery box, which is safe, reliable, simple in structure and high in economy and can be changed rapidly, is provided for an electric automobile.