Abstract: We matched teleseismic P waveforms of the Bohai earthquake (July 18, 1969, Ms 7.4) recorded at 20 WWSSN stations with synthetic seismograms. The following source parameters are obtained: seismic moment M0 = 2.61019Nm; duration of source rupture 12s; depth H = 35km. The two nodle planes are (1) strike angle =24, dip angle = 85, rake angle = 170; (2) = 115, = 80 and = 5.