Direct growth of InSb on Si(111) substrate is achieved by suitably adjusting the growth rate and substrate temperature. In this report, we detail the role of stoichiometry and growth temperature in the evolution of reflection high-energy electron diffraction (RHEED) patterns, surface morphology and the crystal quality. InSb is grown on Si(111)-(7 X 7) surface by evaporating In and Sb simultaneously. Results indicate that smooth heteroepitaxial InSb films could be grown up to 300 degrees C, and above this temperature, severe degradation in the epitaxial quality of the films is observed. Properties of the Sb-rich films an compared with those of In-rich films and the importance of stoichiometry in the crystal quality is discussed.