To investigate the relationship between indium content and optical properties during epitaxial growth of an InGaAs/GaAs single quantum well (SQW), simulation and experiments are demonstrated. The epitaxial growth is demonstrated with low-pressure metal–organic chemical vapor deposition. Photoluminescence (PL) spectroscopy is applied to research the PL properties at room temperature. The In/(In+Ga) varies from 0.24 to 0.36, resulting in an increasing of the full-width half-maximum (FWHM) with the wavelength exhibiting a red-shift. A SQW with an In/(In+Ga) of 0.36 is manufactured, where a FWHM of 23.9 meV is obtained. An InGaAs SQW sandwiched by GaAsP is prepared, which is observed to exhibit a diminished FWHM of 17.0 meV with the wavelength revealing a blue-shift.