Abstract: The standard k-ε turbulence model,QUICK schemes,non-uniform grid and SIMPLE method were applied to the calculations of flow field characteristics for the modeled sealing labyrinth with heating boundaries.It is aimed at investigating the effect of heating boundary.The velocity,temperature and pressure fields were obtained and the flow characteristics were discussed.The computational results state that the leakage goes down as heat flux of the heating boundary rises,and thus the sealing effectiveness under different pressure ratios is enhanced.The results also show that the sealing effect and the heat flux are linearly related.The uneven distribution of the heat transfer causes to produce small eddy at the cavity of the labyrinth and an increase in the sealing effectiveness.The location and size of the small eddy depend on the heat flux on the wall of the heating boundary and the pressure ratio.