An active InGaN layer is introduced on the existing Si-based solar cell technology to improve the energy harvesting at wider solar spectrum. The percentage content of Indium in Indium Gallium Nitride (In_xGa_1-xN) is much affecting the performance of InGaN/Si solar cell. As the In_x content increases, the Ga_1-x decreases accordingly as a result various compositional In_xGa_1-xN compound semiconductor structure would appear on Si. Thus, this difference of Indium content make band bowing of InGaN from 3.42 eV (0% Indium content) to 0.7 eV (100% Indium content) which enhances absorption at wider solar spectrum as compared to single Si cell. Obviously it appears to make efficient management of photon and improve the performance of InGaN/Si solar photo voltaic. The performance of InGaN/Si solar cell is analyzed in this study by varying the Indium content in InGaN. InGaN/Si solar cell is designed by using N-type highly pure crystalline c-Si wafer using wxAMPS software. Indium content in the InGaN is varied to obtain the best composition of InGaN for performance optimization in terms of V_oc, J_sc, FF and efficiency. From the analysis, it is found that medium-ranged Indium content (40%-50% Indium) shows the best performance for InGaN/Si solar cell and it seems to be matched with the underneath Si cell current density as series configuration.