In0.49Ga0.51P is highly promising due to its favorable lattice-matching properties with GaAs, making it well-suited for various device applications. This study investigated the influence of Zn doping on the ordering and optical properties of In0.49Ga0.51P grown on GaAs using metalorganic chemical vapor deposition. By precisely controlling the doping flow, the ordering degree of In0.49Ga0.51P was systematically modulated. The luminescence origin and bandgap characteristics of In0.49Ga0.51P were examined through temperature-dependent photoluminescence and Hall measurements. The findings demonstrate a noticeable peak shift, accompanied by a increase in the bandgap and a corresponding decrease in the ordering degree as the Zn concentration increases.