The damage process of TiN thin film has been studied and the elastplastic shear-lag approach which consider the plasticity of substrate is proposed to evaluate the damages under the monotonic loading. In order to assert the validity of the present approach, we conducted the elastoplastic FEM analysis based on the strain increamental theory. The present results have good agreements with FEM results. The strength properties of TiN film were obtained with the Monte Carlo simulation using the present approach.