Abstract: This paper proposes a synthetic regression analysis method for more than one straight lines possessing the same slope but different intercepts. If X, Ysatisfy the linear correlation:Y=KX+Ci, Ci= 1, 2, hellip;, Nthen the synthetic regression coefficients K, Ci and their standard errors may be solved for by the method of least squares.Eighty stations and ninteen earthquakes in the eastern six provinces and nearby region of China were selected. The seismographs used are short-period ink-recording instruments. The Lg wave propogation velocity was determined to be 3.54 km/s by the synthetic regression method. The anelastic attenuation coefficient is found to be 0.00435+0.00010km-1 for 1Hz Lg Airg phase, and 0.00305+0.00010km-1 for 1 Hz Lg non-Airy phase. The former coefficient is the attenuation coefficient of the medium; the latter possesses statical significance, and may be applied to the establishment of MAXmagnitude formula, aliogether 555 sets of travel-time data and nearly 600 seta of amplitude data of each of LGZ, LGH, MXZ, MXHphase were utilized. The extent of epicentral distances is about 50-1100 km.