With light magnesium oxide （0.5 μm） powder as raw material， rare earth neodymium oxide and cerium oxide as additives， and polyvinyl alcohol as binder， a type of magnesia ceramics was created by sintering at 1 550 ℃ for 2 h and pressing molding under atmospheric pressure of 242 MPa. Then， the hardness， thermal shock resistance， micro structure and phase of the samples were investigated. Firstly， the influence of single rare earth with different additive contents on the magnesia ceramics'' hardness and thermal shock resistance was investigated， and the optimal addition amount of neodymium oxide and cerium oxide was 3% and 8%， respectively. Then， the effects of mixed rare earth neodymium oxide and cerium oxide on the properties of magnesia ceramics were also studied. The results showed that when the content of mixed rare earth was 3% and the mass ratio of Nd₂O₃ to CeO₂ was 3∶7， the magnesia ceramics manifested the best performance， the hardness was 68 HRA， and the thermal shock resistance was up to 19 times.