The invention discloses a swimming and diving dual-purpose appliance, which comprises a fixed-shape cover body and flexible swimming trunks, wherein the fixed-shape cover body covers a swimmer from a head part to a trunk part; the flexible swimming trunks cover the swimmer from the trunk part to foot parts and is connected with the fixed-shape cover body to be of an integral structure at the trunk part of the swimmer; at least one side of the front and rear sides, which cover the back part or the thoracoabdominal part of the swimmer, of the fixed-shape cover body is provided with a breathing pipe hinged onto the fixed-shape cover body, and is provided with a breathing pipe elastic element to make the breathing pipe vertically erected on the fixed-shape cover body; the front end of the part, which covers the head part of the swimmer, of the fixed-shape cover body is provided with a buffering device; an in-cover buffering material is laid and lined inside the fixed-shape cover body; at least one pressurization device is arranged among the fixed-shape cover body, the flexible swimming trunks and the body of the swimmer; the fixed-shape cover body is provided with a visual information collecting device; the tail ends of the flexible swimming trunks are provided with bionic caudal fin sealing rings which are bound in an annular groove of a bionic caudal fin fixing rod fixed between two legs or two feet of the swimmer.