Abstract: The non-subject professional subcontract is an important part of the current "Design-Build model", which greatly improves the modern professional project management system, but the current research on project subcontract management has not yet taken into account the impact of the time value of subcontracting funds on project benefits. Aiming at this problem, the discounted flow time-cost problem model considering subcontracting been proposed on this paper. Combining the ant colony algorithm with heuristic parallel computing mechanism, the optimal net present value under different resource constraints is optimized. The study shows that, when considering the subcontract payment situation, we can get more valuable project scheduling plan, and reduce the project construction costs while improving the production efficiency.