Abstract: The study analyzes the impact of costs on the total investment of Chợ Cồn combined apartment, and shopping mall project in Da Nang City, and figures out the correlation between costs, and total investment. This study also evaluates costs' impact on investment decisions, and proposes solutions to minimize risks, and optimize total investment. The research methods include risk assessment, sensitivity analysis, and correlation assessment between costs, and total investment. The results help project managers better understand the correlation between costs, and total investment, make effective decisions, and propose solutions to reduce risks, and optimize the project. The article also proposes specific solutions to ensure success, and sustainability for Chợ Cồn combined apartment, and shopping mall project. The results, and comments can be applied to similar construction projects, contributing to the development of the field of project management, and investment