Magnesia ceramics is made from MgO powder as raw material， Pr₆O₁₁ as additive， and PVA as binding agent， through dry-pressing molding and pressureless sintering methods. We investigated the crystal phase， sintering properties， hardness， morphology and thermal shock resistance properties of MgO ceramics， which was made at the sintering temperature of 1580℃ for 3h. The Pr₆O₁₁ was added for investigation into the effect of different contents of RE oxides on sintering， hardness， and thermal shock resistance of MgO ceramics. The results showed that the Pr₆O₁₁ had certain enhancement effect on the sintering properties （density and shrinkage ratio） of MgO ceramics but not very much； however， the hardness and thermal shock resistance of MgO were significantly enhanced， and when the added Pr₆O₁₁ content ω was 8%， MgO ceramics enjoys the optimal hardness and thermal shock resistance properties， which were 60.1HRA and 17times， respectively.