Lean premixed combustion is one of the new technologies of pollutants reduction in gas turbines. The main problem of premixed combustion is flashback. CFD modelling is used to simulate the combustion of premixed swirl burner that uses different types of fuels. Flashback simulation studies are performed for a wide range of fuels, operating conditions and burner design. The results show many approaches to reduce the flashback.The flashback can be reduced by lowering the turbulent intensity, adding Carbon Dioxide to the fuel, using fuel blends specially in the case of Hydrogen combustion and/or operating with lean premixed mixtures. Experiments are carried out to validate the results obtained by the CFD simulation and confirm the model validity.