Abstract: This paper presents a relay chain network technology to consider mutual cooperation, cross construction, and resource allocation between working processes in the network plan, on the basis of the relay chain theory, relay chain seamless handover technology, and network planning technique. This technology can make activity handover conduct smoothly, optimize the resources allocation, and improve project quality in ensuring the duration. Its construction of relay chain network, relay-potential calculation, activity handover process, and critical path algorithm, are systematically elaborated. Its application to concrete construction duration and quality control in the third phase of the Three Gorges project has achieved a completion of the dam block A all reaching the design dam top elevation in advance to the planned duration, creating a construction miracle of concrete dam without a crack.