Abstract: In this paper the "moment functions" U and V are introduced to represent the bending moment, torque and transverse shearing force in a thin elastic plate, and therefore the equilibrium equations for bending of the plate become identical relations. The compatibility relations satisfied by U and V are analogous to the equilibrium equations for displacements u and v in plane elasticity. in the paper the boundary values of U and V are prescribed on clamped,unsupported and simply supported edges of plates and compared with those of u and v.The analogy allows us to use a plane elasticity BEM program for calculating bending problems of a plate. The approach is more convenient, since the corner conditions and higher order singularities in usual BEM for plate are circumvented.Finally, numerical examples are provided to show the feasibility and the advantages of the present approach.