孕震系统是一个开放的复杂巨系统，系统具有层次结构，因此应分层次建立孕震系统的力学模型。作者从地球整体观出发，提出了单元体应力水平群体涨落模型，该模型为孕震系统宏观层次上的力学模型。这一模型可以作为几个地震带或几个地块内的地震活动频度、相关转移、时空分布及各类定点观测手段异常台项数群体涨落、时空转移、震后异常等研究的物理基础。 Earthquake earthquake system is an open and complex giant system, the system has a hierarchical structure, so should establish a mechanical model of seismogenic system. Starting from the perspective of global holism, the author proposes a population fluctuation model of unit stress level, which is a mechanical model on the macroscopic level of the seismogenic system. This model can be used as the physical, physical and chemical properties of seismic activity in several seismic zones or in a few blocks, correlation transfer, space-time distribution, basis.