In order to quantify the dimensional stability in CFRPs, the water diffusion considering an anisotropy and moisture expansion behavior are investigated. Water diffusivity coefficients were determined by measuring the specimen weight during the moisture absorption test. The diffusivity coefficients of three main axial directions are obtained from three shape specimen's result and solving simultaneous equations. A 3-dimensional locator using laser-displacement measurement was employed to measure micro deformation of the CFRP specimens. The curvature of surface was observed due to the distribution of moisture contents. The coupling analysis, which includes mechanical deformation and thermal diffusion, was conducted. The numerical results are in good agreement with the test results.