In order to study the influence of thermal curing on the later strength and microstructure of high-performance concrete with mineral admixture, the strength test and pore structure analysis of high-performance concrete with mineral admixture are carried out in the different constant temperature durations and the different temperatures of curing. The results show that compared with the standard curing, the thermal curing can quickly increase the early strength of concrete, but the higher the thermal curing temperature, the longer the thermal curing time, the greater the damage to the later strength of the concrete and the greater the porosity. The strength loss at 80℃ thermal curing for 48 h after transferring to standard curing for 28 d is 4.4 times that at 50°C, and the total porosity is 1.091 times. Compared with the standard curing and the natural curing, the post-curing method is to use Ca(OH)2 saturated aqueous solution curing, which can improve the later strength and pore size distribution of the thermal cured concrete to a certain extent.