The surface morphology is one of the important factors to determine the optical properties of colloidal quantum dots. Colloidal CdSe dots were synthesized by the injection of precursor molecules in a hot surfactant, and a series of samples were obtained by partially replacing the ligands on the surface of these dots with 2-mercaptoethanol. 2-mercaptoethanol results in the decrease of the photoluminescent quantum yield, and the time-resolved photoluminescent (PL) spectra are significantly modified. The effect of the surface morphology is discussed.