The present invention provides a floating and waterproof sound box including a bottom house, the bottom house has a two-layer structure and includes an inner rear house located in an inner layer and an outer rear house located in an outer layer, the inner rear house is entirely enclosed, the outer rear house has a two-layer structure, at least one water inlet is defined in an outer layer of the outer rear house, and a water storage space is defined between the outer layer and in an inner layer of the outer rear house. The floating and waterproof sound box of the present invention can float over flowing water without being overturned or sinking and the inner rear house is entirely enclosed so that water penetration is avoided.