A nano-porous silicon film deposited on a flexible cyclic olefin copolymers substrate is adopted to insulate the structure at high processing temperature during device manufacturing. In this study, the thermal conductivity of nano-porous silicon film modeled by Lysenko et al.  is implement to do the one-dimensional heat conduction analysis and to calculate the temperatures theoretically and numerically. In numerical work, the COMSOL finite-element based package is used for the numerical computations and effects of applied temperature loading, thickness of nanoporous silicon layer, and porosity are discussed. As shown in the analysis results, thickness of 200μm has the lowest temperature than other thicknesses, 25μm, 50μm, and 100μm, etc. Porosity plays a vital effect for thermal insulation. From the analyses, the case of 80% porosity has the larger temperature decrement than cases of 40% and 60%. It may be attributed to the lower conduction by higher porosity. Also, these temperatures show good agreement between the theoretical and numerical results and are consistent to the Lysenko et al.  statement for nano-porous silicon film for thermal insulating material.