To test the ecological waterway construction level in the tidal estuary，we carry out the evaluation study. According to the natural conditions，ecological environment and channel attributes of tidal estuary，we analyze the connotation characteristics of tidal estuary ecological waterway and put forward an evaluation indicator system for it. Taking the South Passage of the Yangtze River Estuary as a case，we select appropriate indicators and evaluate the waterway health index. The results show that the waterway healthy index value of the South Passage after the first phase of navigation channel regulation project is 0.884 6，reaching good level. The regulation project greatly improves the conditions of river regime and enhances the channel conditions. Navigating conditions and water-related function are pretty good. Habitat and biological conditions are in the middle level，consistent with the ecological environment background state of the Yangtze River Estuary. The effect of ecological waterway construction in South Passage is remarkable.