The branch of science that studies the macroscopic mechanical properties of continuous media. Macro-mechanical properties refer to the material properties dominated by Newtonian mechanics in three-dimensional Euclidean space and the uniform elapsed time. Continuum mechanics has no assumptions about the structure of matter. It is not contradictory to the theory of material structure, but complementary. Material structure theory studies the material properties of special structures, while continuum mechanics studies the same properties of many substances with different structures. The main purpose of continuum mechanics is to establish the mechanical model of various substances, determine the constitutive relation of various substances in mathematical form, and find the solution of the problem under given initial conditions and boundary conditions.