The invention relates to an anticorrosion expansion compacting agent composition and a preparation method thereof; the composition comprises the following components by weight: 15-35% of aluminium-containing compounds, 0-8% of zirconium-containing compounds, 2-10% of magnesium salts, 0-3% of titanium dioxide compounds, 0-6% of lithium salts, 2-6% of alkanolamine salts, 0-10% of super-plasticizers, 0-10% of solidification adjusting agents, 0-5% of acids, and the balance of carriers. The components are reacted in a reaction vessel at 80 DEG C+/-5 DEG C for 3 hours, and then cooled to 45 DEG C+/-5 DEG C; thermal insulation is performed for one hour; and anticorrosion expansion compacting agents of a standard type, a solidification-promoting type, or a pumping slow-solidifaction type are obtained according to the added solidification adjusting agents with different types and amounts.