Abstract: Epitaxial growth of manganese and manganese silicide on Si（100）-2×1 reconstructed surface at different temperatures was studied using ultra high vacuum molecular beam epitaxial-scanning tunneling microscopy system（UHVMBE-STM）.The results showed that when the temperature of substrate was controlled from room temperature（RT） to 135℃ in the growing progress,the products were manganese nanoclusters which were almost in the same size;when the substrate temperature was elevated to 210℃,manganese began to react with Si,and there were manganese silicide nanowires on the substrate;when it was up to 330℃,the nanowires on the substrate were totally replaced by stick-like manganese silicide and three-dimensional（3D） irregularly-shaped silicide islands.Along with the deposited temperature increasing,the relationship between the nucleation density of the products and the deposition temperature was well in accorded with that the classical nucleation theory of the two-dimensional（2D） island growth.