EGR (exhaust gas recirculation) technology can significantly reduce NOx emissions from an engine, especially when used in conjunction with an EGR cooler tank. This paper presents the calculation method, building model, simulating of the cooling tank, applying numerical simulation to calculation and design of EGR coolers. The results show that with the EGR rates of 30% and 40% the selected cooling tank structure as a tube-beam heat exchanger, it is completely possible to use the heat exchanger tubes, which are smooth tubes, to meet the cooling needs of the circulating gas when the lowest possible cooling temperature is down to 115˚C for the circulating gas at the outlet of the cooler and the maximum flow of water to be supplied to the pump is 0.911kg/s. Ansys Fluent software is used in this paper to study the flow field and temperature distribution inside the cooler.