Abstract: The modified couple stress theory (C1 theory) in the isotropic elasticity is extended to anisotropic composite laminated plate. Based on virtual principle, a new model is established for a single layer of composite laminated thin plate involving two material characteristic length constants. In the theory the form of new curvature tensor is asymmetric，however it can result in the same symmetric curvature tensor as in the isotropic elasticity. More simplified model for cross-ply composite laminated thin plate involving one material length constant is applied to the buckling analysis. Numerical results show that the present plate model can capture the scale effects of buckling analysis in microstructures.