Sulphoaluminate alite cements were successfully prepared fromfly ash, bauxite and CaF2 as a fluxing agent by designing MG and MS values, i.e., the controlling of CaO and CaSO4 content, and the sintering at 1150℃, 1200℃, 1250℃, 1300℃ and 1350℃ respectively. The effects of composition design and calcining temperature on the mineral phase of cement clinker were investigated by XRD and SEM, and the chemical reaction route and mechanism were discussed in this paper. The results indicate that the optimized mineral phase of cement clinker can be obtained under the following conditions: MG=1.05 and MS =0.95 at 1300℃, and the phase compositions of cement clinker are C4A3S 58.73%，C3S 23.99%, C2S2.87%, C11A7·CaF2/C12A714.07%，and f-CaO 0.35%. The main phase C4A3S in the cement clinker is well developed into regular and perfect rhombus-dodecahedron morphological crystals with sizes of 1～3μm, and the alite phase is developed into smaller hexagon crystals. 