Each of the current analytical methods used in rock and soil CT mechanics is 'observation', wasting the precious CT quantitative information. Utilizing the CT number, the perfect degree and the damage-fracture degree of a point inside the rock sample are defined, the level perfect field, the level damage-fracture field and the 1-2 level intercepted section are defined according to the level perfect degree and the level damage-fracture degree, the size of the level perfect field, the level damage-fracture field and the 1-2 level intercepted section can be accurately calculated avail of the measure theory and the set theory. Perfect space and damage-fracture space of the rock and soil media are established based on the above conceptions. The paper paves a new way for the quantitative analysis of the rock and soil mechanics by means of the CT datum, simultaneously establishing the foundation of the rock and soil damage-fracture space mechanics. If the level is magnified from the mesomechanics value to the macroscopic one, this method is suitable for the macroscopic geotechnical mechanics, the uniform description of the macroscopic mechanics and the mesomechanics is realizing, the uniform description of the continuum mechanics and porous media or crannied media mechanics comes true, too.