With the passage of time, the Inner Harbour of Macao has experienced changes, prosperity and decline. For a long time, the twin problems of flood and transformation of the traditional business district have been the ones primarily responsible for affecting the development of the Inner Harbour. This paper analyses the Inner Harbour region through the form of five layers. Based on these factors, the cultural, economic and ecological characteristics of the Inner Harbour are summarised. The paper mainly studies solutions to the problems of flooding, and presents flood control initiatives that can prevent waterlogging in the Inner Harbour, so as to enhance and activate the old city waterfront.