The merging of gravity and the gauge principle has been a central thread in the century-long exploration of theoretical physics ever since the birth of general relativity. Taking the perspective shift from the “geometric paradigm” to the “matter paradigm” as its guiding thread, this paper systematically traces the two major stages of this merging process. The first stage takes the gauge principle as its starting point, passing through Utiyama’s local Lorentz gauge theory, Sciama’s spin-torsion coupling, Kibble’s Poincaré gauge gravity, and culminating in the Riemann-Cartan spacetime geometry and gauge field theory framework established by Hehl and others, thereby profoundly revealing the intrinsic connection between the gauge principle and spacetime gravity. Nevertheless, this stage consistently follows the traditional paradigm of “starting from spacetime geometry.” The second stage, marked by the gravitational quantum field theory proposed by one of the present authors, realizes a fundamental paradigm shift: the gauge symmetry SP (1,3) corresponding to the spin of elementary particles is established as an independent and primary intrinsic symmetry of the fundamental building block. From this, entirely new structures such as biframe spacetime and a noncommutative, fiber-bundle-like gravitational gauge spacetime emerge, enabling gravitational dynamics to be naturally derived from the basic principles of quantum field theory and breaking through the framework limitations of traditional curved spacetime geometry. This paper systematically expounds the historical trajectory, core physical ideas, key mathematical structures, and characteristics of field equations of the two major stages, compares and analyzes their essential differences and internal connections, and elucidates the theoretical self-consistency of constructing the generalized standard model and achieving a unified description of the four fundamental interactions within the framework of gravitational quantum field theory.