Abstract: Wall-bounded turbulence at high Reynolds numbers is one of the most important problems in engineering design and applications, and its high efficiency and high precision simulation method has always been one of the most important research realms in turbulence research. Constrained large eddy simulation (CLES) is one of the new simulation methods proposed in recent years. Differently from the traditional hybrid RANS/LES method, the CLES method performs a LES calculation in the whole field. In the inner region near the wall, it uses the constrained subgrid-scale model, while in the outer region, it uses the traditional subgrid-scale model. With nearly 10 years' efforts, the CLES method has been verified in incompressible/compressible attached wall-bounded flows and incompressible/compressible separated flow. Further-more, it has also been successfully used to simulate the complex flows in the aviation field. In this paper, the basic principle of the CLES method will first be reviewed, followed by some discussions on the CLES implementations. Finally, some possible future research directions on the CLES method are summarized.