Abstract: Taking the malmstone as the experiment and research object,based on the erosion effect of aqueous solution with different pH values,concentrations and components,a series of immerse on tests and triaxal compression experi- ments are conducted to compare and analyze the micro structure characteristics,deformation features,intensity damage and deterioration mechanics of its mechanical parameters of the malmstone under different water chemistry circum- stances. The test results indicate that the increasing acidity and basicity and the higher concentration lead to more strong corrosion behavior towards the malmstone. Besides,the chemical corrosion turns the malmstone from fragility in- to ductility and leads to the deterioration of mechanical parameters. Under the same condition,the deterioration degree of cohesion is higher than that of internal friction angle,and the deterioration degree in acid solution is higher than that in alkaline solution. In addition,the concentration of Ca2+ and Mg2+ in the solution,as well as the pore rate,shows a positive correlation with the deterioration degree of the mechanical parameters,while the relative mass difference of specimens Δm shows a negative correlation with it. Moreover,the new defined porosity damage parameter is capable to accurately reflect the damage evolution process of mechanical parameters of specimens under the chemical water-rock interaction.