Mixture of magnesium oxide with either silica fume or phosphate were prepared in this research. The workability, mechanical properties and the microstructure of the two magnesium based binder were examined. Compressive strength tests showed that the magnesium phosphate cement (MPC) gained early strength much faster than magnesium silica hydrate cement (MSH) but the MSH system showed continued long term strength gain. The results from XRD testing confirm that MgKPO4·6H2O was the main hydration products of MPC and for magnesium silica system there was a considerable amount of brucite which co-existed with MSH. Scanning Electronical Microscopy was used to examine the microstructure and nature of the hydration for both Mg based cements.