InfiniBand is one of the most promising network interconnecting technologies in HPC. Its reliable connection services support RDMA, atomic operations, etc, and are widely employed in MPI and other similar parallel programming models. However, the cost of message queues and buffers for reliable connections rises dramatically when the scale of parallelism increases. As a result, it becomes the bottleneck for InfiniBand in large scale applications. ho solve the problem, this paper provided shared receiving queue and extended reliable connection, then brought forward the group connection technology based parallel communication mode. On hand, the memory cost in the computing node is cut down for at least 100 times smaller. And the most amazing thing is that the cost of memory will be relatively constant when the scale of parallelism is upgraded.