Diffuser augmented tidal turbines are getting enormous attention due to their immense potential to increase the generated power output. Researchers around the globe are investing considerable time and financial resources in this domain. Limited research results are available for diffuser augmented tidal turbines due to their emerging nature, large and costly research and development setup, startup cost and proprietary issues. Turbine enclosed in a diffuser is based on the principle that the generated power output by a tidal turbine is directly proportional to the cube of velocity of incoming fluid flow. Thus, even a minor increase in velocity considerably increases the generated power output. The diffuser helps accelerate the incoming fluid flow. Hence, the efficiency of the turbine is significantly increased by using a diffuser. It is challenging to accelerate the incoming flow by using a diffuser due to its shape, geometry and fabrication limitations. The diffuser design requires great deal of innovation and time investment. The purpose of this paper is to present the study of 2D model of diffuser for tidal current turbine. The study involves developing a 2D CFD model of diffuser, acquiring simulation results and comparison with experimental results. The mesh is generated in ICEM followed by simulation in CFX. The simulation results are compared to experimental results and found in reasonable agreement. The research is essential to utilize CFD tools for diffuser design used for tidal current turbine.