Abstract: The cooperative communication system with three full duplex source nodes was studied. In order to improve the effectiveness and reliability of the system, two space-time coding schemes for full duplex cooperative communication between two sources were proposed. The orthogonal space-time coding theory was applied to improve the performance of the system by effectively utilizing the spatial diversity gain, resisting multipath fading. The scheme was divided into sharing and transmission phase and cooperative transmission phase. In the sharing and transmission phase, the information was shared between the sources and sent to the destination node. In the cooperative transmission phase, virtual MIMO was formed between the source nodes to send information to the destination node. The outage probability of each receiver was deduced. The simulation results show that, compared with the traditional source node transmission scheme working in half duplex mode, the scheme can effectively improve the throughput and the outage probability performance. At the same time, when the outage probability is 10^-3, the scheme has a signal-to-noise ratio gain of about 1.5 dB, and compared with the non-cooperative transmission, the scheme has a signal-to-noise ratio gain of about 8 dB.