According to the problem of low efficiency of the network transmission system based on Transmission Control Protocol(TCP) in the case of large time delay and loss rate，this paper proposes an efficient method for network transmission system based on digital fountain. The principle of the digital fountain is described and a new system is designed and implemented on the basis of Raptor codes and User Datagram Protocol(UDP). The results are given and indicate that the transmission efficiency of this new method is greatly improved compared to that of the traditional one.