Systematic investigation of InAs quantum dot (QD) growth using molecular beam epitaxy has been carried out, focus-ing mainly on the InAs growth rate and its effects on the quality of the InAs/GaAs quantum dots. By optimizing the growth rate, high quality InAs/GaAs quantum dots have been achieved. The areal quantum dot density is 5.9× 1010 cm?2, almost double the conventional density (3.0 × 1010 cm?2). Meanwhile, the linewidth is reduced to 29 meV at room temperature without changing the areal dot density. These improved QDs are of great significance for fabricating high performance quantum dot lasers on various substrates.