The load imbalance of sensor node is a severe problem for Wireless Sensor Networks (WSNs). In this paper, we firstly propose a Multi-hop Multi-relay Network Model (MMNM) with Relaying Head (RH) to balance the load among sensor nodes. And the emergence of energy harvesting techniques brings us the Energy Harvesting Wireless Sensor Networks (EH-WSNs). Due to the indeterminacy of energy that can be harvested in ambient environment, study on energy management mechanism to achieve energy neutral is significant. We proposed a novel Sensor Nodes Pair (SNP) policy dividing all the sensor nodes into two groups GSN and GSN'. With the function rotation of GSN and GSN', we achieve continuous data transmission avoiding time delay. Also a Historical Harvested Energy Assigning Mechanism (H-HEAM) is proposed to ensure the energy neutral constrains and perpetual network operation. Extensive simulation results verify that our MMNM and H-HEAM are indeed able to improve the network overall performance on throughput, energy utilization efficiency and time delay.