Group III-nitride alloys are believed to be promising photoelectrodes for photoelectrochemical water splitting to get hydrogen fuel. Here, we grew the InGaN nanowires (NWs) on silicon (111) as a photoanode using a low-cost chemical vapor deposition method. The photocurrent of an InGaN NWs' photoanode is five times greater than that of a GaN NWs' photoanode. The maximum photocurrent density of 8 mA/cm2 at 0.5 V vs the reverse hydrogen electrode with an applied bias photon-to-current efficiency of 5.8% was observed in the In30Ga70N NWs/Si (111) heterostructure. The incident photon-to-current conversion efficiency of 19.1% at 520 nm was observed for In30Ga70N NWs' photoanodes, which is much higher than GaN NWs. The hydrogen generation rates are 42.3 μmol/cm2 h at 0.15 V under 100 mW/cm2 white light irradiation. This InGaN/Si heterostructure photoanode improves photoelectrochemical performance for hydrogen fuel generation, paving the path for future development at a lower cost and on a larger scale.