A new method using foraminiferal test walls was introduced to infer the ecology and paleoecology of foraminifera and the paleoenvironment of sediment/water interface. Two optically different walls known as a radial texture and a granular one, which have been used for the systematic criteria, can be applied for the analysis of foraminiferal microhabitat. Their variations have been recognized for distinctly and indistinctly radial textures, and jagged and mosaic granular textures, respectively. A microgranular texture is another type of the granular texture. The variations of the granular texture can be quantitatively examined by measuring the area and the perimeter of a crystal unit. The rations of the perimeter (P) to the area (A) of the crystal units are reasonably discriminated for three different types of granular textures. Despite little knowledge of foraminiferal ecology, the taxa with higher P/A rations indicate deep infaunal and lower oxygen microhabitat and in turn those with lower ones indicating epifaunal or shallow infaunal and higher input of phytodetritus to the sediment surface.