In the traditional use of Distributed-Space Time Block Codes（D-STBC）in the relay system

matrix relay nodes generated code words need to control message overhead without changing the relay node number

which is not suitable to the practical communication scenarios.In order to solve the problem

we propose a new method of D-STBC coding.The method introduces D-STBC in traditional multiple input multiple output system and uses the AF forward agreement.The Relay nodes don’t require the control message when generating code word matrix and cooperating with other nodes.Therefore

the adaptability of the communication system of collaboration and performance of the system can be improved.Finally

the MATLAB simulation results show that the method has more superior performance in full diversity and full rate conditions with low decoding complexity.