Abstract: Network coding is a new technology in the field of data transmission. In network coding, nodes are allowed to encode the data received from different nodes so that bandwidth utilization and network throughput can be improved. Whereas, if there are some selfish nodes in the network, these selfish nodes will delay or refuse coding and forwarding. It will increase the delay of network coding and reduce the efficiency of communication. When the problem gets more serious, the network coding will break off, and communication chaos will arise. In order to solve this problem, the motivation scheme based on detect-defray mechanism for selfish nodes of network coding is proposed. In the motivation scheme, firstly, the delay of nodes for encoding and forwarding will be detected, which can be the cost of network coding. Then it operates the defrayment part, in which network coding is regarded as a kind of economic behavior, and source nodes are consumers, and intermediate nodes are providers, and remuneration will be defrayed for providers from consumers when defrayment mechanism operates. Since intermediate nodes benefit from network coding when providing services, the enthusiasm of intermediate nodes for network coding can be improved, meanwhile the delay of network coding will be reduced. Scheme analysis shows that, the motivation scheme can reduce the delay of network coding and control the nodes' selfishness effectively. Finally, the effectiveness of network coding can be improved.