This paper discovers geometric unification theory of the grand unification and gravitational interactions and their new physics according to the general fiber bundle theory, symmetry and so on. Consequently, the research of this paper is based on the exact scientific bases of mathematics and physics. The Lagrangians of the grand unification and gravitational interactions are unifiedly deduced from quantitative causal principle (QCP) and satisfy the gauge invariant principle of general gauge fields interacting with Fermion and/or boson fields. The geometry and physics meanings of gauge invariant property of different physical systems are revealed, and it is discovered that all the Lagrangians of the four fundamental physics interactions are composed of the invariant quantities in corresponding spacetime structures. The difficulties that fundamental physics interactions and Noether theorem are not able to be unifiedly given and investigated are overcome, the geometric unification theory and origins of the four fundamental physics interactions and Noether theorem are shown by QCP, their two-order general Euler-Lagrange Equations and corresponding Noether conservation currents are derived in general curved spacetime. This paper further deduces QCP from symmetric principle. Consequently, geometric unification theory of the grand unification and gravitation theories and Noether theorem based on symmetric principle and the new physics are given in this paper. This paper further gives the unification of QCP and symmetric principle. Thus, this paper opens a door to both study and give new developments of geometric unification theory of physics laws, and using the new geometric unification theory, a lot of research works about different branches of physics can be anew done and expressed simpler with different symmetric characters.
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