Abstract: A series of Mg-Al acid-base compounds were prepared by coprecipitation method，and the effects of solid base and acid properties on the catalytic performance were studied. CO2-TPD and NH3-TPD results showed that the prepared Mg-Al compounds have both were weak acid and weak basic sites. The catalyst exhibited the best activity for acetone condensation to isophorone when the acid amount was 0.21 mmol/g and the basic amount was 0.015 mmol/g.