Change of moisture content in the ambient air results in nonuniform crosssection moisture profiles and generates warping deformation because of asymmetry of hygroexpansion. In order to support the design of bamboowood composite flooring, the moisture content(MC) changes and the deformation ratio of bamboowood composite flooring was investigated in dry conditions using thermalstructure coupled analysis with ANSYS software. Wood and bamboo are assumed to be orthotropic materials, and adhesive layer is assumed to be homogeneous material in this model. The influence of the core layer thickness and surface layer thickness of the bamboowood composite flooring is taken into consideration in the model. The simulation results show that the adhesive layer between the surface and the core layer acts as a water vapor barrier because lower moisture diffusion coefficient, so the MC of the surface layer changes with the environment condition. However, the MC of the core and backing layer remains stable. The thickness of the surface has an impact on the time needed for the floor to reach the equilibrium MC and the maximum cupping deformation. Thickness of the core layer rather than the surface has great effect on the cupping deformation ratio of bamboowood composite flooring.