An optical contact angle measuring instrument was used to measure the static contact angle of cuticle surface, prismatic layer surface and nacre surface in cyclina sinensis. The result showed that the three surfaces are hydrophilic: the contact angle of cuticle surface is about 35°, the contact angle of prismatic layer surface is about 45°, and the contact angle of nacre surface is about 36°. The observation of the microstructure of cyclina sinensis surface by the scanning electronic microscope showed that its prismatic layer surface is consist of micron-size spherical structure, the diameter of sphere is 2.5∼4µm, the distance between spheres is about 0. The hydrophilic mechanism of prismatic layer surface in cyclina sinensis was analyzed and the result indicated that it is accord with Wenzel model. Its hydrophilic property depends on the effect of micron-size spherical structure of prismatic layer surface and the components from the body surface layer. The surface roughness of the three surfaces in cyclina sinensis was measured by using the confocal laser scanning microscope.