In this paper,on the basis of the combination pattern,author calculates two models by using the 3-D finite element method. The major conclusions are:(1)The adjustment element fractures firstly before the strong earthquake takes place,variation of strain with time is a quasi-lambda curve.(2)The accumulative element will fracture after the adjustment element fractures,variation of strain with time is a lambda curve.(3)The strain attenuates quickly along the perpendicular direction of fault strike,but slowly along the fault strike.(4)The situations of the clements in a seismic field region are very complex,and their strain changes with time are non-lambda curves. Finally,some seismic events about lambda-pattern are presented,and some precursory phenomena are interpreted by using conclusion(1).