Wireless sensor network is becoming more and more popular in recent years; but energy-constrained characteristic of sensor nodes is one of the critical issues that we must consider in system design. In this paper,a cluster-based virtual V-BLAST transmission scheme is proposed to achieve energy savings for energy-constrained wireless sensor networks. In the proposed scheme,instead of using cluster member as cooperative nodes,multiple cluster heads cooperate to form virtual antenna array so that V-BLAST based virtual MIMO transmission can be implemented. Based on the communica-tion energy consumption model,a way to optimize the parameters for the scheme is given. In addition,detailed simulation is performed to evaluate the performance of the proposed scheme for both densely and sparsely deployed sensor networks. Theoretical analysis and simulation results verify the energy efficiency of the proposed scheme.