Battery support structure of vehicle body

A battery support structure for a vehicle body according to the present invention includes a plurality of battery supporting members which are provided on a bottom side of a rear floor of the vehicle body and support a battery unit. The plurality of battery supporting members have a plurality of cross members for battery support extended in a width direction of the vehicle body. A pair of side seals are installed on both sides of the rear floor. A rear cross member is installed on a bottom side of the rear floor. At least one cross member for battery support among the plurality of cross members for battery support is connected to the rear cross member and the side seal. Accordingly, the present invention can improve the driving performance of a vehicle.