Lung cancer has become one of most killing disease in 20th century. There are various external and internal causes identified by experts to be the causes of this disease. Various type of treatments have been developed taking account on the stage and condition of cancer itself, such as Radiation Therapy, Chemotherapy and Surgery. In this paper, a method called Thoracoscopy is focused for improvement by investigating a possibility of using finite element method (FEM) to predict deformation and movement of tumor during lung lethargy process as a preparation stage for this surgery method to be deployed. Thoracoscopy is suitable for stage-I cancer, as it will only create a small incisions on the skin and has high possibility to cure by removing the tumor. This paper used a commercial FEM tool to model lung in 3-dimension and by using tested data of material properties, a simulated result of lung lethargy process was compared with experimental data. Results revealed a few promising points to further develop this virtual capability and use it to predict deformation prior the surgery.