In the present investigation, we examine systematically the dynamical behaviour of the architecturally complex bimetallic surface alloy, namely, Pt(110)–(2×1)Cu, which is characterized by a half-monolayer (0.5 ML) of copper atoms deposited on a platinum (110) substrate. By leveraging Newtonian mechanics within the harmonic approximation, we construct the dynamic matrix pertinent to the bulk material. The extraction of eigenvalues and eigenvectors is pivotal in formulating a robust theoretical framework, anchored in the Green’s function approach explicitly designed for our model system. Utilizing this sophisticated theoretical model, we are able to elucidate the phonon dispersion relationships traversing the high-symmetry pathways ГY, YS, SX, and XГ of the surface Brillouin zone, as well as deduce the associated local vibrational densities of states. An extensive interpretation of the computational results reveals a notable phenomenon, namely, the electron redistribution between the platinum and copper atoms within the alloy interface, which, in turn, altered the interfacial force constants. This electron redistribution prompts significant divergences in the vibrational density of states at the individual platinum and copper atomic sites at the Cu/Pt(110) juncture, as opposed to the undisturbed Pt(110) surface, suggesting potential pathways for innovative platinum-catalysed surface reactions. Furthermore, our research delineates the variation of several thermodynamic properties as a function of surface composition and thermal parameters, which may offer insights into the stability and reactivity of such bimetallic surfaces.