The clinckers were obtained when a raw mixture consisted of limestone, slags and gypsum was burned at 134$0^{circ}C$ for 30 minutes, and 128$0^{circ}C$ for 30 minutes adding $CaF_2$ as a flux. The principal compounds of these clinkers were $C_3S_2$, $eta-C_2S$, $C_1A_3{ar{S}}$. To investigate hydration behavior, cements were made and hydrated at constant humidity cabinet (W/C=0.5 20$pm 1^{circ}C$). X-ray diffractometer, SEM, and conduction calorimeter were employed to examine the hydration behavior. The hydrates were mainly C-S-H, ettringite, $Ca(OH)_2$. By the hydration of $C_3S$ and $C_4A_3ar{S}$, the needle-like ettringite filling the inner vacant spaces of the hardened body might contribute to the rapid-hardening and high-strength phenomena. Furthermore, the hardened body became stronger due to the hydration of $C_2S$ at later period. The addition of granulated blastfurnace slags have a potential to be a blended cement.