In order to reduce the leakage of the labyrinth seal,a seal structure with a groove at the front end and the rear end of the seal tooth of the straightthrough labyrinth seal was proposed.Based on the CFD method,a numerical simulation model of the labyrinth seal was established.The correctness of the model was verified by comparison with the existing experimental data.The applicable range of different turbulence models was discussed,and the differences in leakage,axial pressure drop and flow field velocity distribution of smooth surface,front groove and rear groove were compared.The results show that the SST turbulence model is more suitable for the nearwall flow of the narrow gap of the labyrinth seal.The front groove structure has a poor effect in reducing the leakage amount,and which can reduce the leakage amount only under the high pressure difference.The rear groove structure can change the direction and state of the vortex in the labyrinth seal cavity,thereby weakening the gas barrier effect of the labyrinth seal,increasing the energy dissipation of the seal and reducing the leakage amount.Therefore,the labyrinth seal structure of the rear groove has engineering application prospects.