Abstract: In this paper, a mathematical model for the problems of bending of elastic of elastic plates is established. In this mathematical model. we presented three arbitrary functions to express the bending couples、twisting couple、shear forces and angular rotation and transuerse deflection etc. mechanical quantities which satisfied equiliber ium equations. For example, considered Reissner model. If let the sign A. ψ and R to note above three arbitrary functions respectively, then functions A, ψ and R need to satisfy the following equations:
△△A=q/D,
△ψ-10/h²ψ=0,
and
△R=-(1-2μ)/10μ q/D,
and where μ is Poisson's ratio. The above first two equations are known, while the third is new.