Amorphous SixC1-x films possess the potential to improve wear performance in humid atmospheres and at higher temperatures. But some experimental work on the films showed that silicon contents greatly influenced their microstructures and mechanical properties. Therefore, simulations of molecular dynamics were carried out to predict structures of the SixC1-x films at different silicon contents. The results show that the sp(3)/sp(2) ratio of all the films increases, but the stiffness of the films is decreasing with an increase in silicon contents. Moreover, silicon atoms are almost surrounded by carbon atoms, which is in agreement with the experiments. (C) 2011 Elsevier B.V. All rights reserved.