Abstract: Under the same cement content,there existed obvious strength differences between the stabilized soil samples formed from soil samples with different pH values,which was adjusted through chemical agent.In order to find the reason of these experimental results,concentrations of main ions in the pore solutions squeezed from the stabilized soil samples were measured,and the concentrations of Ca(OH)2 in the pore solutions with many ions were calculated by the thermodynamic method.It was shown that,under the same cement content,when the pH value of soil samples was low,the concentration of Ca(OH)2 in the pore liquid of the stabilized soil could not reach saturation;at this stage,the higher the pH of soil was,the more the hydrates generated by cement hydration,therefore the higher the strength of the stabilized soil was;after the concentration of Ca(OH)2 reached the saturation point,the hydrates would fully grow and the strength of the stabilized soil would reach the maximum.