Cash flow of a construction project can be defined as the amount of money that comes in and out during the course of its life cycle. It is the net amount of money that changes hands throughout the entire life cycle of the project. A positive cash flow means that more money is coming into the project than going out, while a negative cash flow signals that more money is going out than coming in. Cash flow of a construction project is essential in determining its success and should be closely monitored to ensure the project stays on track for completion.