With similar components to human bone, hydroxyapatite (HAp) has been commonly used in dental and orthopedics practice. Calcium phosphate cement (CPC) can be made into porous HAp scaffolds through reaction; therefore, this study aims to examine how reaction temperatures influence CPC. CPC powder and NaCl are blended, and after diammonium phosphate (DAP) is added, they are infused into a mold for a hydration reaction under a saturated vapor pressure to form CPC scaffolds. XRD and FTIR are used to determine the influence of reaction temperatures on crystallization and functional groups. A scanning electron microscope (SEM) observes the structures of the CPC scaffolds. Test results show that when the temperature of a saturated vapor pressure is 70 °C, the CPC scaffolds have significant crystalline conversion and functional group peaks. SEM observation indicates that the temperature of a saturated vapor pressure does not affect the formation of the CPC scaffolds structure.