Based on density functional theory, the structural and electronic properties of two-dimensional passivated SiC monolayers have been systematically investigated. It is found that the electronic structures of SiC monolayer can be evidently adjusted by surface functionalization and biaxial strain. The band gap (4) of SiC monolayer becomes larger after passivated by hydrogen, while it decreases by halogen atoms. The E-g of SiC monolayer decreases monotonously when the biaxial strain varies from -0.129 to 0.129. In contrast, the variation of Eg for passivated SiC monolayer displays an arc-shape during the investigated range. The Eg decreases with increasing compressive or tensile strain. (C) 2015 Elsevier B.V. All rights reserved.