Cash flow is a core element for enterprises to maintain operations and development. Cash flow forecasting models, through systematic analysis of an enterprise’s historical cash flow data, trends in operating activities, and external environmental factors, scientifically predict the scale, direction, and fluctuation of cash flow within a certain period in the future. This article focuses on the application of cash flow forecasting models in enterprise investment and financing decisions, sorts out the types and core functions of the models, analyzes their specific roles in investment project screening, financing plan formulation, risk prevention and control, and fund allocation, points out the existing problems in current applications, and proposes optimization paths. Research shows that the scientific application of cash flow forecasting models can enhance the accuracy and rationality of enterprises’ investment and financing decisions, and help enterprises achieve sustainable development.