Abstract: P·Ⅰ cement was prepared by using titanium gypsum and a mixture of titanium gypsum and natural gypsum to study the possibility of making use of titanium gypsum as setting retarders. The basic physical properties and hydration heat characteristics of P·Ⅰ cement were studied. The phases and microstructures of cement hydration products were investigated by XRD and SEM. The results showed that adding titanium gypsum would increase normal consistency, shorten the setting time, and its strength is same as which using natural gypsum. With the increase of dosage of titanium gypsum, the normal consistency of double mixed titanium gypsum and natural gypsum cement increase, and the setting time first increases then decreases. When the titanium gypsum dosage is 2.50%, the setting time reached longest, as the dosage increased from 1.25% to 3.75%, its 28d compressive strength is higher than the control group. The soundness of P·Ⅰ cement with titanium gypsum could meet the demand, the setting time, normal consistency and strength are conform to the standard.