The aperture and its distribution have remarkable influence on permeation behavior,infiltration rate and filtration character of porous bodies.In this paper,the methods in common use for determining the aperture and its distribution of porous materials are introduced,including the direct observation from cross-section,the gas-bubble method,the permeation method,the mercury method,the gas-adsorption method,the liquid-liquid method,the suspension-filtration method,the X-ray small-angle scattering method,etc.And several measuring methods are compared with one another.Considering the complexity of apertures and various influence factors in the determining of aperture,it is important to determine the proper method according to the structure characteristic of the material,moreover,the test error must be considered.