Abstract: Ultra-high toughness cementitious composites (UHTCC) have excellent performance in toughness and energy absorption. The damage law of UHTCC functionally graded slabs under contact explosion is numerically investigated using LS-DYNA software to design a protective structure with excellent performance. The anti-explosion property of the structure is discussed considering the effects of the target material, explosive content, reinforcement arrangement and energy absorption layer thickness. The results show that the UHTCC functionally graded slabs exhibit excellent blast resistance under blast loading as a consequence of the reduction of craters, scabbing and target damage, and the increase in blast waves absorption. Especially, the target damage can be effectively reduced by arranging the tie ribs and rationally setting the thickness of the energy absorption layer.