This experiment has been carried out for the purpose of investigating the effect of $V_2O_5$ and $H_3BO_3$ additives on sintering of magnesium oxide over the temperature range of 1300-150$0^{circ}C$ MgO powder has been obtained by calcin-ing extra reagent grade magnesium carbonate(basic) at 90$0^{circ}C$ for 30 minutes. The specimens were prepared by compression with pressure of 700Kg/cm2 then fired at 1300-150$0^{circ}C$ for 0-5hrs. Sintering behaviour and microstructure of fired specimens were examined. Densification rates obeyed the equation D=K 1n t+C. The ratio of density in case of addition of $V_2O_5$ to theoretical density of pure periclase was 95-99% Activation energy of densification in case of $V_2O_5$ addition was 30.15 Kcal/mole. The range of average grain size in case of addition of $V_2O_5$ was 40-50$mu extrm{m}$. $H_3BO_3$ addtivie had not an effect on densification of MgO.