The influences of curing conditions on the pore structure of cement based material with different water binder ratios were investigated via mercury intrusion porosimetry(MIP). The results show that curing condition has substantial influence on the pore structure of cement based material. Compared to the saturated curing, the sealed curing increases the pore content(mass volume) in 1001000nm but decreases that in <10nm. By sealed curing the specific surface area of cement based material is decreased, while the porosity(by volume) for pastes is increased, but the porosity for mortars has less obvious change. The secondary cementitious material, ground granulated blast furnace slag(65%, by mass) and silica fume(5%, by mass), show limited capacity to resist the pore percolation by self desiccation.