We report a systematic study on modulating optical properties in gallium antimonide (GaSb) with the sulfur surface passivation. Compared with the pristine sample, the intensity of the photoluminescence (PL) emission from the passivated GaSb was dramatically enhanced about 15 times at room temperature. The temperature-dependent surface states were further investigated via the low temperature PL spectroscopy. The bound-edge-related transition emission (BE4) at 795 meV and the residual acceptor associated emission located at 777 meV were identified clearly at 10 K. The observed passivation effects on the photoluminescence characteristics evolution of GaSb are discussed in detail. Crown Copyright (C) 2012 Published by Elsevier B. V. All rights reserved.