In order to develop concrete generating compressive strength of 10MPa 10MPa∼∼15MPa aging for 6hours in the room temperature curing, Hardening accelerator containing Ca 2+ mixed with rapid hardening portland cement containing CC33S S in quantity. The result was that the more addictive contents of Hardening accelerator is, the more greatly early compressive strength was improved. That That’’s because the composition of Ca(OH) 22 was mass-produced at early-ages.