Due to their particular optical characteristics, metallic island films have the potential to significantly increase the energy conversion efficiency of solar cell. We experimentally and theoretically investigated the effect of substrate temperature on the morphologies and optical properties of the silver island films. At low temperature, below 300℃, as the substrate temperature increases. Compared to the films prepared at room temperature, the sizes of nanoparticles decrease and the absorption peaks shift to shorter wavelength accompanied by an increase density resulting in a 150% absorption efficiency. As the substrate temperature goes up to 300℃, nanoparticles with larger in-plan(X-Y) dimensions are formed, the number density decreases and the absorption peaks redshift but the absorption efficiency is still 10% higher. Numerical simulation reveals that these behaviors are a consequence of morphologies transformation.