A series of MgO catalysts for the oxidative coupling of methane prepared by different methods have been investigated. Specific surface area, XRD and XPS measurement results reveal that at lower temperatures catalysts with larger specific surface area, larger lattice distortion, smaller crystal dimension, and higher amount of unsaturated coordinated surface oxygen give higher catalytic activity. However, if we compare the catalytic properties of the samples in terms of unit surface area, the dependence of catalytic properties of the samples will be different.