InGaN-based solar cells with p-InGaN/i-InGaN/n-GaN double heterojunction structure have been fabricated and characterized in our study. Two kinds of sapphire substrate, conventional sapphire substrate and pattern sapphire substrate, were used for epitaxial growth of the heterojunction structure. Both the solar cells grown on conventional sapphire substrate and pattern sapphire substrate demonstrated high open-circuit voltage (Voc) of 2.05 V and 2.08 V, respectively. However, short-circuit current density (Jsc) of solar cell grown on pattern sapphire substrate shown an improvement of 27.6% when comparing to its grown on conventional sapphire substrate. Such an enhancement could be contributed to the increase of effective light absorption path due to the incident light scattering from textured surface on pattern sapphire substrate.