This study theoretically investigates the electronic structures and photophysical properties of isomeric triangular macrocyclic gold(I)?biphenylene complex (MPP) using quantum chemical calculations and wavefunction analysis methods，aiming to elucidate the physical mechanisms underlying their linear and nonlinear optical spectra.The molecular orbital characteristics were analyzed via highest occupied molecular orbital (HOMO)?lowest unoccupied molecular orbital (LUMO) analysis，density of states (DOS)，one?photon absorption (OPA) spectrum，as well as static and 280 nm resonance Raman spectra， thereby revealing the regulatory mechanisms of electronic excitation features and molecular vibrations on linear spectral properties. The electron excitation characteristics of MPP were further visualized using charge difference density (CDD) maps and transition density matrix (TDM)，clarifying the influence of charge transfer and localized excitations on optical responses.Additionally，the core physical features of nonlinear optical behaviors were characterized by computing molecular (hyper)polarizability to explore its nonlinear optical response patterns.Results demonstrate that MPP exhibits a strong absorption peak at 280 nm in linear spectra， with molecular vibrational modes significantly modulating Raman spectral features.In nonlinear optical aspects，MPP shows pronounced nonlinear anisotropic characteristics，and the (hyper)polarizability decreases with increasing wavelength.