Abstract：In order to study the effect of heat-moisture cycle on the strength and impermeability of HPC, the influence of the number of wet-heat cycles on the compressive strength, splitting tensile strength and water absorption of HPC30, HPC50 and UHPC concrete was tested. The results showed that the compressive strength of HPC30 and HPC50 increased with the increase of the number of hot and humid cycles (0～90 times) and later (90～300 times). The compressive strength of HPC30 and HPC50 increased with the earlier numbers of cycles, and decreased with the increase of the later numbers of cycles. The compressive strength of UHPC decreased with the increase of the numbers of cycle. The splitting tensile strength of the three kinds of concrete increased first and then decreased with the increase of the numbers of damp heat cycles. Increasing the number of hot and humid cycles, HPC30 and HPC50 will improve the impermeability, while UHPC impermeability will reduce.