Against the backdrop of deep integration between new-generation information technology and enterprise management, the integration of business and finance has become a core driving force in promoting the digital and lean transformation of engineering project management. This paper addresses issues in traditional engineering project management, such as the disconnection between schedule management and financial control, data silos, and delayed decision-making. Taking the construction of Shenyang Design Institute’s digital management platform as a case study, it systematically elaborates on the practical approach to lean schedule management in engineering projects under the concept of business-finance integration. By establishing a real-time linked control system centered on specific projects and integrating multi-dimensional schedule indicators — including planned progress, visual progress, owner settlement progress, collection progress, revenue progress, management expense disbursement progress, and payment progress — and by leveraging automatic data synchronization, visual comparison of leading-edge lines, and intelligent early-warning rules, the system achieves collaborative visibility and dynamic adjustment of business flows and value flows throughout the project lifecycle. Practice shows that this model significantly enhances the accuracy of project schedule control, the timeliness of risk prediction, and the scientific nature of management decisions, providing a valuable reference for engineering enterprises in advancing digital transformation and refined management.