Abstract: In this paper, on the basis of intensity data from 85 earthquakes that occurred in China, the method of resolving overdetermined equations by using the damped least squares method is applied to inversing for the mean value of 1-sec. S wave quality factor, the spreading factor and the source S wave acceleration in 7 regions of China. The relation between soures S wave acceleration and magnitude is discussed. As an example, 2-D Qs distribution in Taiwan Province is obtained by inversion. It is found that there exists some correspondence relation between this distribution and Bouguer gravitational anomaly and seismicity.Preliminary analysis and discussion on results of the inversion, and estimation of error in Qs are made.