The invention discloses a preparation method of a pre-opened foam aluminum sandwich plate. In a riveting process, large deformation of a foam aluminum porous structure is not involved and the problemthat a foam aluminum plate is partially compressed and deformed in a riveting process to warp and damage a peripheral material is solved. The invention further discloses a self-piercing riveting device and method of the pre-opened foam aluminum sandwich plate and a metal plate; the pre-opened foam aluminum sandwich plate is produced and a semi-hollow self-piercing rivet is adopted; the cylindricalmetal plate for assisting molding is placed in a foam aluminum sandwich plate hole and a riveting process is transformed into connection between thin plate materials, so that the self-piercing riveting device and method can be used for connecting the foam aluminum sandwich plates with different thicknesses; in the riveting process, damages to the foam aluminum porous structure are avoided and a connector has good sealing performance and mechanical properties.