This research paper delves into the critical domain of risk assessment for mega infrastructure ventures by proposing and evaluating an integrated approach that harmoniously combines quantitative and qualitative models. The study recognizes the multifaceted nature of risks in large-scale projects and addresses the limitations of singular assessment methodologies. Through an exhaustive literature review, the paper establishes the necessity of a holistic risk management strategy and outlines the methodology for integrating both quantitative and qualitative models. Drawing upon real-world case studies, the paper demonstrates the application of the proposed approach in diverse mega infrastructure settings. Results indicate a synergistic effect, offering a comprehensive understanding of risks that traditional methods might overlook. The integrated model not only enhances the accuracy and reliability of risk assessments but also provides valuable insights for effective decision-making. This innovative approach contributes to the advancement of risk management practices in the field, providing a solid foundation for future research and practical applications in the realm of mega infrastructure development. Keywords: Risk Integration, Holistic Risk Management, Mega Infrastructure Projects, Quantitative Metrics, Qualitative Factors, Decision Support Systems.