The Effect of Dditives $ZrO_2$ and $TiO_2$ on the enstatite body the composition of which was MgO.$SiO_2$ has been closely investigated on the physical properties and microstructure. $ZrO_2$ and $TiO_2$ as additives were added by weight 5, 10, 15, 20, 25% and 1, 2, 2.5, 5, 10, 20% respectively to the mixture (MgO : SiO2=1:1) and fired at the temperature ranging from 130$0^{circ}C$ to 145$0^{circ}C$ and 1275$^{circ}C$ to 1375$^{circ}C$. Increasing the add ition or $ZrO_2$ to 20% the physical property became better. In case of $TiO_2$ the sample containing 20% $TiO_2$ had a best effect on the enstastite body. The optimum firing range proved to 14$25^{circ}C$ for $ZrO_2$ and 1325~135$0^{circ}C$ for $TiO_2$. The effect of $ZrO_2$ and $TiO_2$ addition on the thermal expansion was observed not ot be remarkable.