Abstarct: The aim of Computational Fluid Dynamics (CFD) is to analyse systems such as flow current, heat transfer and other chemical phenomena with computer programming . CFD is very capable for technological and non-technological usage. It has been developed very much during several years. MAC is one of the well- known methods for modeling of flows in CFD. For fluid flow the governing equations can be solved using numerical methods. baxses of these equations are Momentum and Continuity leading to Navier-Stokes equations. There are several methods such as Simple, PISO and Fractional Step for solving these equations. In solution procedure, it needs to decide where to store pressure and velocity components. Two type of meshes, namely staggered and colocated grids can be used. On staggered grid, the velocity components are stored at the cell face and the scalar variables such as pressure are stored at the central nodes. However on colocated grids, all parameters are defined at the same location at the central nodes. The aim of this project is to study using of MAC method by colocated mesh for modeling flow in channels. Also the results of colocated mesh is compared with staggered mesh and with Open Foam and Ansys results. Using MAC algorithm for colocated meshes is first studied for finite difference in chapter four and then is studied for finite volume method in chapter 5. All codes are written by visual C++ language and they all are attached in apendix part of this thesis.