In response to rapidly changing situations, cross-organizational cooperation has become a common phenomenon. Organizations have begun to carry out innovation activities with the help of the cooperative relationship, which could comprehensively enhance their work efficiency. Also, the technological innovation network will change in time and space. Therefore, it is of great significance to map these changes and identify their rules for improving the construction quality and innovative capability in the AEC (Architecture, Engineering and Construction）field. However, few pieces of research have been done in this field.

Based on the Tien-yow Jeme Civil Engineering Prize of China, this paper generates the innovation collaboration network of megaprojects by using a dynamic meta-network analysis method, analyses its evolutionary characteristics, and identifies its key nodes. The results show that the innovation collaboration network of megaprojects with Tien-yow Jeme Civil Engineering Prize is a small-world network with low density and polycentricity. However, the key organizations with high centrality and intermediary are not the same. 

Then this paper takes a deeper look into the spatio-temporal evolution characteristics of the whole network by examining the consistency index of project location and enterprise location, since the region exerts the vital influence on AEC organizations among characters of "region, industry, internal and external environment". Therefore, the result shows that the companies whose headquarters locate in big cities in eastern and central areas of China occupy the critical positions in the network. Beijing, Shanghai, Wuhan, Guangzhou, and Chengdu have become AEC innovation centers in the north, east, middle, south, and west respectively. However, there are few large-scale AEC innovation organizations in the northeast, west and southwest, which reflects the imbalance in regional development. When the influence of time is taken into account, it is found that the value of index measuring geographical consistency remains stable at 0.5 after 2003, which means that local enterprises gain no superiority over external competitors in project construction. With the enhancement of the bidding system and complexity of the project, foreign enterprises began to participate in the bidding, which brings more choices for entrepreneurs. Location and technical strength have become both important facts for entrepreneurs to make decisions, which greatly weakened the strength of local companies.

In order to study the evolving characteristics of the cooperative network further, this paper summarizes the historical network of Tien-yow Jeme Civil Engineering Prize, which shows the characteristic of polycentricity. But the center of the network is not obvious. It also shows that megaprojects ′s technological innovation does not depend on a few key organizations, but is driven by regional innovation centers emerging with the development of the whole industry. When the paper takes a further look at the characteristics of the key node within the network, the paper finds that a little number of enterprises have become key nodes of the network over time. What′s more, state-owned enterprises have become the main body of innovation network, and local enterprises play an intermediary role within the network. This is mainly due to the advantages of state-owned enterprises in technology, employees′ quality, resource and social capital.