In this project propose, we have decided to design and analysis of Gas turbine internal cooling passage using Computational Fluid Dynamics. Already there are various types of cooling methods are used in turbine blades. One of the most commonly used methods is internal cooling of the turbine blades. In that trailing edge is an important role to cool but the difficult is to design the cooling passage. So we decided to design and analysis of two pass trapezoidal smooth channel with different inlet and outlet width and 88º tilted divider wall which is separate the two channel. The L shape and opening in the L shape divider wall is introduced to cool the trailing edge .The advantage of this channel reduces the temperature rate in the trailing edge and also the channel by using the tilted divider wall. In the first three cases inlet width is less than that of outlet width and the next three cases inlet width is greater than that of outlet width. This model is designed and analyzed by using ANSYS FLUENT and the flow testing analyzed at the range of Reynolds number 10 X 105. The flow is considered incompressible, three dimensional, turbulent and steady with constant thermodynamic properties. When analysis the different cases we concluded that the design of L shape divider wall with the inlet width is greater than that of outlet width is more efficient and reduce the temperature rate.