Abstract: The separation of n-pentane，n-hexane and n-heptane mixture with the dividing wall column (DWC) was simulated with commercial software HYSYS，and the optimized operation region was obtained. The effects of feed property，such as feed thermal state，feed composition and relative volatility，on the operation of DWC were studied. The results demonstrated that the feed thermal state influenced strongly on the optimized operation region. And with the increase of the light component in the feed，the stable operation of DWC became more difficult. Furthermore，the simulation showed that relative volatility played an important role in energy saving and the operation of DWC. The more difficult the separation between the components，the better the effects of the separation. But the optimal operation region becomes narrow and unstable.