In this work, the large eddy simulation (LES) method is used to study the instantaneous and time-averaged characteristics of flow and heat transfer in three internal structures i.e., swirl cooling (SC), impingement cooling (IC), double chamber cooling (DC) in the leading edge of a turbine blade at three Reynolds numbers (6.0 × 103, 9.0 × 103, 1.2 × 104). Comparison with RANS method, LES method can provide internal cooling designers with a more comprehensive understanding of flow and heat transfer. The numerical results reveal the following important conclusions: (1) At the view point of time-averaged, the tangential jet in SC and DC can significantly increase the heat transfer rate (Nu), and therefore their heat transfer rates (Nu) are higher than that of IC, but IC has the lowest friction resistance. (2) At the view point of unsteady analysis, the flow instability of SC along the flow direction increases with Re, while the flow instability of DC decreases. The heat transfer rate (Nu) instability of IC is the highest, at Re = 6.0 × 103, the Nu fluctuation amplitude of IC is increased by 34.9 % compared with SC.