A MgO - partially - stabilized ZrO2 foam ceramic is reported. The optinum sintering temperature of MgO -ZrO2 foam ceramic is in the range of 1730~1760℃. The tetragonal ZrO2 precipitates in C -ZrO2 matrix can be retained by using cooling rate of 300℃/h after sintering. Ageing at IIOO'C for 3 h after sintering increases the bending strength and thermal shock properties of MgO - ZrO2 ceramic foam. The ceramic foam was very effective in reducing oxide inclusions in high temperature alloy.