At present, soil structure is generally estimated quantitatively by either three phases of soil or degree of aggregation. In this paper, in addition to three phases of soil, the author investigated more synthetic process using air permeability, oxygen diffusion rate, oxygen demand and moisture characteristics, and divided the degree of aggregation in detail into remolded, water-stable and non-water-stable ones. The proposed process consists of a series of the above mentioned measurements and it is performed saving as much samples as possible. As a result of the following field test, this process can be applied to a macroscopic estimation of soil structure, such as the changes with time or location, and the influence of land use.