The self-organized InP nanostructures grown on GaAs(001) substrates by metalorganic vapor deposition were examined in detail using atomic force microscopy. By properly selecting growth temperature, three kinds of nanostructure, islands, pits and ripples were formed. For growth temperature of 400–450°C, the surface morphologies were governed by islands; but, for the growth temperature of 500°C, the formation of surface ripples instead of islands was presumably due to the combination effect of temperature-controlled surface kinetics and strain effect. On the other hand, the observation of enhanced growth of pits upon a high-temperature annealing (at 685°C for 90s) indicated that the strained InP epitaxial film would be morphologically stabilized by taking the form of pits formation.