In recent years, with advances in medical treatment, the demand of medical beauty market has increased year by year. With the continuous innovation of nanotechnology, medical technology with nanometer level is becoming the one of the most important issue of the development of medical biotechnology in recent years. In order to make the products effective, the products have to be transported into the human skin. In traditional medical treatments, the devices of contacting type or invading type were adopted, and might cause some infected problems. To avoid these situations, some medical companies have developing the non-contact type device¡Ð gene gun. This device use nitrogen as motive force to atomize the thin film of the injection products, then delivering these products to derma. This research utilizes computational fluid dynamics software to build the FEM simulation model of Venturi tube inside of a gene gun. Then, analyzing the speed and atomization of fluid which inside or outside of Venturi tube. A FEM simulated mechanism for the atomization of multiphase flow was constructed in this research successfully. The effects of variations of some geometric parameters of Venturi tube on the atomization of thin film were studied also. The obtained results can shorten cost and time in relevant development.