The optical properties of self-assembled InAs quantum dots (QDs) on GaAs substrate grown by metal-organic chemical vapor deposition (MOCVD) are reported. Photoluminescence (PL) measurements prove the good optical quality of InAs QDs, which are achieved using lower growth temperature and higher InAs coverage. At room temperature, the ground state peak wavelength of PL spectrum and full-width at half-maximum (FWHM) are 1305 nm and 30 meV, respectively, which are obtained as the QDs are finally capped with 5-nm In0.06Ga0.94As strain-reducing layer (SRL). The PL spectra exhibit two emission peaks at 1305 and 1198 nm, which correspond to the ground state (GS) and the excited state (ES) of the QDs, respectively.