Abstract:The Shanghai Expo AB area construction project was taken as an example to discuss the relationship of project complexity and time limit for it, and human cost under the four scenarios of parallel, sub contract, organization structure and members optimization by means of the simulation software ProjectSim. It is concluded that in some cases there are no conflicts between the project complexity, time limit and its human cost, and that all of them can be optimized simultaneously through increasing relevant personnel on key positions, which is totally different from the traditional view that time limit is often in conflict with human cost.