Abstract: In order to adapt plate and shell models in applying the finite element method to tectonic analysis problems in representing crustal layer,this paper relaxes the synmmetrical restrictions on the geometry and elasticity in the multi-layered structure.According to the effective principle we re-determine the location of the neutral plane of the plate,which is no longer in the middle of the plate as in the synmmetrical case.General expressions for effective bending stiffness and elastic moduli are given,they are expressed in terms of each layer's thickness and elastic moduli of the plate.Two examples are given for three-layer crustal model.We also discuss the difference between the effective bending or membrane stress distribution and those obtained by treating each layer in their own moduli.