Abstract: Concrete porosity is one of the most important indices for the appraisal of concrete feature. This paper, through the study and verification on several test methods of porosity for hardened cement paste, adopted a method for measuring concrete porosity by methanol displacement, which can measure the overall porosity of concrete including the boundary surface structure porosity of aggregates. This method is simple and easy to be used, it is expected that the method may be used for detecting the construction quality of concrete and appraising its durability.