Wood plastic composites(WPCs)have been gaining market share in the exterior materials such as decking because of their good durability. However, the durability of WPCs is much influenced by their ratio of wood flour to plastic. Therefore, simple methods for quantitative analysis of wood and plastics in WPCs are desired. In our previous study, it was possible to quantify the ratio of wood or plastics in the case of WPCs which consisted of wood and polypropylene(PP)with simple methods using DSC and FTIR-ATR. However, the recycled plastic which used as raw materials of WPCs often contains not only PP but also polyethylene(PE). Therefore, it is necessary to test the applicability of our analysis methods to WPCs which contains PE and PP. In this paper, we try to construct calibration curves to quantify the ratio of wood and PE by using DSC and FTIR-ATR analyses of WPCs which consisted of wood and PE. A combination of calibration curves obtained for wood and PP in the previous study and those acquired for wood and PE in the present study were applied to the quantitative analysis of the WPCs verification sample which was manufactured with a predetermined prescription using PP/PE mixture as plastic raw material. As a result, it was shown that the wood to plastic ratio in the verification sample could be calculated with a relatively good accuracy when FTIR-ATR method was used.