A novel magnesium phosphate cement made from magnesia and potassium phosphate was studied. The objective of the study was to examine the basic characteristics and cementing mechanism of the cement. The effect of magnesia content on setting time, temperature rise during initial reaction and strength development of the cement mortar were examined. The reaction products of cement with water, and cementing structure were also examined. The results show that the cement was rapid setting and had high early strength. With the increase of magnesia content, the setting time of cement became shorter and the temperature rose higher during initial reaction. Compressive strength was also increased with increasing magnesia content. The microstructure of the hardened cement was studied by X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy. The reaction product in the cement is magnesium potassium phosphate hexhydrate (MgKPO.6HO-MKP). Thomas Telford Ltd © 2011.