Abstract: InAs nanostructures were grown on stripe-configured GaAs(100) substrates by a combination of pre-prepared patterned substrates and droplet epitaxy using molecular beam epitaxy. InAs quantum dots were found totend to form close to the platform as well as on ridges or sidewalls, and the variation of InAs quantum dot morpholo-gy depended on the diffusion limitation of In atoms on the patterned substrate. With the increase of the substratetemperature and the extension of the annealing time, almost all InAs quantum dots at the bottom of the trench gradu-ally disappear, while growing and ripening on the platform. Based on the nucleation and diffusion of In atoms on pat-terned GaAs substrate, the mechanism that In atoms preferentially nucleate on the plateau and climb upward on thepatterned GaAs surface is found. Based on this mechanism, the effects of annealing time, substrate temperature, andEhrlich-Schwoebel barrier on the nucleation and diffusion of In atoms on the patterned surface are systematicallydiscussed.