The mineral transition mechanism and physicochemical property of calcium aluminate clinker sintered at 1350 °C were systematically studied using analytical reagent α-Al2O3, CaCO3 and SiO2 when the molar ratio of CaO to Al2O3 is 1.0. The results show that the formation of Ca2SiO4 accelerates the diffusion of CaO and Al2O3, which promotes the formation of CaAl2O4 determined by dilatometer, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy methods. CaAl4O7, Ca3Al2O6, Ca3SiO5 and Ca2Al2SiO7 only exist in the initial stage of reactions, the amounts of which decrease with the increase of sintering duration. Ca3Al2O6 and Ca12Al14O33 react with Al2O3 and CaAl4O7 to form CaAl2O4, while Ca2Al2SiO7 reacts with CaO and Ca12Al14O33 to form Ca2SiO4 and CaAl2O4. The sintered clinker contains CaAl2O4 and γ-Ca2SiO4 as well as some Ca12Al14O33 when the sintering duration is longer than 1.0 h. The differential scanning calorimetry results reveal that Ca2SiO4, Ca2Al2SiO7 and CaAl2O4 are formed at 985 °C, 1045 °C and 1339 °C, respectively. Increasing the sintering duration contributes to the transition of β-Ca2SiO4 to γ-Ca2SiO4, which improves the pulverization and alumina leaching property of the sintered clinker.