The invention discloses a preparation method for a concrete inner-maintenance material in an interpenetrated network structure. By taking plant starch, an ionic monomer, a nonionic monomer, a crosslinking agent, an initiator, tetraethyl orthosilicate, an alkali, deionized water and the like as raw materials, the maintenance material is prepared through material preparing, stirring, drying and grinding in water of 50-90 DEG C by virtue of an aqueous solution method. Researches show that the interpenetrated network structure of the material is formed by interpenetrating a starch grafted crosslinking polymer and polysilicic acid resulting from hydrolytic condensation of the tetraethyl orthosilicate. The comprehensive performance, water absorption, water retention and water release, of the material are obviously superior to those of a polyacrylic water-retaining agent, so that the material is more suitable for a concrete alkaline environment. The inner-maintenance material can provide a continuous and effective early inner-maintenance effect for concrete so as to effectively prevent the concrete from cracking at a early stage.