Firstly, this paper discussed the causal relationship between the combination model and stopping phase in seismograms. According to the combination model which was proposed by Guo Zhenjian et al in 1973, there are shear-stress concentration region, tension-stress abdicatation region and weaker medium abdication region at ends of accumulation element. When a rupture propagate from a stronger medium region into a weaker medium abdicatation region, the rupture will be speeded, then stopped quickly, thus stopping phase is produced. These termination factors are caused by the adjustment element of the combination model. The amplitude of stopping phase is related to abdication degree of the adjustment element. The better abdication degree, the more striking stopping phase.
Secondly, this paper took the Tangshan earthquake of July 28, 1976 for example to study the stopping phase and rupture process. The result shows that the Tangshan earthquake is a bilateral rupture, total length is 96 km.