A new simple layer-wise first-order theory(LFOT) with two variables was proposed, in which the shear strain was piecewise first-order function and integration of it through the laminate thickness could fulfill Timoshenko shear strain theory. The equilibrium equation was derived by minimum energy principle and solved by Rayleigh-Ritz method. After comparison with classical first-order theory(CFOT) and test results, it has been shown that the predicted value by LFOT is relatively more conservative than CFOT because of considering skin resistance ...