Agent constriction system is a product of government reforming investment system. Firstly, the definition of agent constriction system was given based on governmental decision. Secondly, agent construction mode was compared with general contract mode from the point of identity, management main body, management objective and character. Moreover, sameness and difference were discussed between agent construction mode and project management mode. Thirdly, Chinese actuality of agent construction system was analyzed. Some important problems have exposed during the operation process. They are about legal status of agent units, agent units’ right, agent charge standard, talents echelon development of agent units. Finally, pointed at these problems, improvement measures were put forward such as improving laws and regulations about agent construction system, cultivating and developing capable agent units, and strengthening performance evaluation of agent units. It is seen that agent construction system is an inevitable tendency reforming project management system.