The invention relates to a foam-filled three-period minimum-curved-surface porous structure sandwich panel and a preparation method, a core comprising three-period minimal curved surface porous structure cells is arranged between an upper panel and a lower panel, and the minimal curved surface porous structure of the core is also filled with a foam material with a certain density. When the sandwich panel is subjected to external impact compression load action; due to the contact coupling effect between a foam filling material and the extremely small curved surface porous structure, the deformation mode of the overall structure of the sandwich panel is changed, so that the mechanical property of the foam-filled three-period minimal curved surface porous composite structure is remarkably improved compared with a hollow minimal curved surface porous structure, and the energy absorption enhancement effect of interaction during two plastic deformation of minimal curved surface porous structure wall surface bending and foam material compression can be exerted. An outer-layer panel is connected with an inner-layer panel, and the inner-layer panel and the core are integrally printed and fused, so that firm connection between the core and the panels is facilitated, and optimal configuration of materials and thicknesses of the inner-layer panel and the outer-layer panel is facilitated.