A three-dimensional numerical study on the turbulent flow and heat transfer characteristics in the rectangular channel with different types of baffles is carried out. The inclined baffles have the width of 19.8 cm, the square diamond type hole having one side length of 2.55 cm, and the inclination angle of 5 degrees. Reynolds number is varied between 23000 and 57000. The SST k - omega turbulence model is used in the method to predict turbulent flow. The validity of the numerical results is confirmed by measurement. Numerical results show that the flow patterns around the different baffle type are entirely different and it significantly affects the local heat transfer characteristics. The heat transfer and friction factor characteristics are significantly affected by the perforation density of the baffle plate. The present study demonstrates that the battle type II (3 holes) can enhance the greatest heat transfer rates with advantages from the overall efficiency point of view.