AES and RHEED techniques have been applied to a study of temperature dependence of the sticking coefficient of In atoms on the Si(lll)4×1-In surface. At temperatures below 110℃, the sticking coefficient for In atoms is close to zero due to saturation of valence bonds resulting from the arrangement of In atoms in the 4×1-In overlayer. The steep change of the sticking coefficient in the temperature range 110-120℃ may be explained by a model of the order-disorder transition arisen from the surface melting. At temperatures above 120℃, the sticking coefficient of In atoms is always close to unity.