Aiming for the load unbalance problem in Low Power and Lossy Networks(LLN) due to uneven node deployment, an Energy-Efficient Routing Protocol for LLN based on Load Balancing(EELB- RPL) is proposed. This protocol has made the following improvements：the optimal parent node is selected by comprehensive examination of the link quality, transmission delay, node residual energy, throughput and congestion detection factor. By adjusting the Trickle timer, the nodes adjust their suppression mechanism according to the network topology density, so as to avoid the suppression unfairness and load unbalance. The simulation results show that compared with the existing algorithms, the EELB-RPL can effectively achieve load balancing where the average packet delivery rate is increased by 14.6%, the throughput of sink node is increased by 28.5% and the network lifetime is increased by 8.96%.