The structural and electronic properties of the interface are critical for the morphology of supported metal nanoparticles and thus the performance in catalysis, photonics, biomedical research, and other areas. To reveal the intrinsic mechanism of the formation of various morphologies, a multiscale simulation strategy is adopted to bridge the macroscopic structures by experimental observations and microscopic properties by theoretical calculations. This strategy incorporates the density functional theory (DFT) for the interaction energy calculation, the molecular dynamics (MD) simulation for the structure evolution, and theoretical model for the correlation with contact angles. The interaction energies between Pt atoms (four-atom clusters) and substrates are applied for the force field parametrization in the following MD simulation. Simulation results show the binding energies and structural properties such as radial distribution function and coordination number for supported metal nanoparticles with various sizes in detail. Notably, the contact angles of supported nanoparticles are well correlated by the strength of metal-support interactions. This work yields guidelines on the structure modulation of supported metal nanoparticles via interfacial control.