The influence of highsilicon limestone on mineral structure and performance of belitebarium calcium sulphoaluminate cement clinker were investigated by thermal analysis, petrographic analysis, Xray diffraction and scanning electron microscopyenergy dispersive spectroscopy. The results show that highsilicon limestone has low decomposition temperature, which can promote the development of C3S by adding small quantity. The formation and development of C3S is hindered by αquartz while C3S is formed easily by mixing magnesite and dolomite in highsilicon limestone at low temperature. When mass proportions of highsilicon limestone and ordinary limestone is 1.0︰5.0, the compressive strength of this cement at 3, 7, 28 d is 37.9, 60.3, 87.9 MPa respectively, which shows excellent improvement of mechanical properties.