Ecological hydrology and water resources optimal distribution has become one of the great scientific research directions. Based on the lowest ecological water level for wetlands, the lowest ecological water demand volumes in Honghe national wetland reserve were estimated by a quantitative combination method of static and dynamic valid ecological water supplements. The results showed that the lowest ecological water level of study area was 51.5m, static water demand was 1863.0×104 m3, and dynamic ecological water supplement distribution as follows, supplement volume per month of first level was 867.4×104-1518.0×104m3, second level 693.9×104-1214.4×104m3, third level 520.4×104-910.8×104m3, fourth level 173.5×104-303.6×104 m3 and fifth level 0.0×104m3. The lowest ecological water level computed by this study was scientific in a sense. The ecological water level enhanced by 30m could provide appropriate environment for hydrophytic succession of wetland plants. It was expected that the results of this study could suggest on effective management of other wetland nature reserves.