Abstract: Porous magnesiums for biomedical applications were prepared by powder metallurgy technology,using atomized pure magnesium powders as raw material and ammonium bicarbonate as space holder.The porosity and the pore size can be controlled through changing the spacer material’s volume and size.The corrosion rate of the porous magnesiums with different porosity were invested in simulated body fluid.In order to improve corrosion resistance of porous magnesium in simulated body fluid（SBF）,alkali-heat treatments was carried out.The phase composition and micro-morphology were analyzed by XRD and SEM respectively.We found that the corrosion rate accelerated when the porosity increased.What’s more,although the corrosion resistance of the specimens after alkali and alkali – heat treatment are both improved,porous magnesiums after alkali – heat treatment have a better result.