This paper is concerned with the real-time controlling for the road construction machinery groups. Multi-agent system is capable to deal with the cooperation in dynamic and distributing environment, according to the characteristics of asphaltum-concrete road construction, the intelligent decision support system (IDSS) model based on Multi-Agent technology is adopted into the road construction. In this paper, a company-like multi-layered multi-agent architecture is proposed. Authors explain the coordination-controlling among the agents in the system, and clarify the real-time decision-making process in constructing. After the debugging in machine groups, the system based on the model can deliberately make and rapidly analyse in the complex instances of construction, put forward reasonable decision advices, and then improve the construction quality and efficiency.