To investigate the ripening behavior of Al droplets on GaAs surface, Al droplets were prepared onto GaAs substrates by droplet epitaxy. The growth and nucleation of Al droplets were effectively controlled by controlling the annealing time without arsenic pressure. By combining thermodynamic principles and crystal growth theories, physical explanation of the different sample morphology and constructed the basic models about ripening, etching and diffusion behaviors during the process of droplets morphology transition were carried out. The calculation results confirm that the droplet will be consumed by etching and diffusion process simultaneously when the ripening behavior reaches the equilibrium state after annealing of 239 s.