PURPOSE : A cash flow analysis method for actively managing fluctuations of factors determining cash flow and automatically/promptly offering cash flow analysis without manipulation of a projector manager in a real estate development project, and a project management system thereof are provided to exclude making a cash flow analysis table manually by automatically updating interconnected items even if the factor determining the cash flow is fluctuated.CONSTITUTION : The factors determining the cash flow and data for monthly preferential withdrawal/construction expense are inputted. Monthly this-month cash income/total cash and preferential withdrawal/total construction expense are automatically calculated by automatically calculating the monthly cash income based on input data for the factors determining the cash flow. Monthly this-month balance-1 and monthly total balance-1 are automatically calculated by subtracting the received monthly preferential withdrawal from the monthly this-month cash income. This-month balance-2 is automatically calculated by subtracting the this-month construction expense from the this-month balance-1, and construction payment and monthly total balance-2 are automatically calculated based on the this-month balance-2.? KIPO 2006