Abstract: Based on the statistical outcomes relevant to elliptical isoseisms in ref. 1, the average focal depths and rupture lengths of faults for earthquakes with different magnitudes or epicen-tral intensities that occurred in the eastern and western parts of China are discussed. A set of intensity attenuation functions appropriate to a point sourse (with focal distance as the distance parameter in the attenuation law) and line source (with the nearest distance from site to rupture line or the everage distance from site to both ends of the rupture line as distance parameter) have been proposed.