A pipeline transmission is the state-of-the-art approach to transmit large amounts of data over IEEE 802.15.4 multi-hop networks, but the performance of the pipeline transmission can be degraded in unreliable networks. In this paper, we propose an efficient multi-path pipeline transmission (EMP) to support the large data transfer with low latency and high energy efficiency under various network conditions. The proposed EMP adjusts cycle time of the pipeline transmission, which allows nodes to retransmit dropped data packet efficiently. It helps to improve the transmission probability, so EMP can mitigate additional delay and energy consumption caused by frequent end-to-end retransmissions. In addition, EMP employs a multi-path transmission which distributes the large data transfer over multiple routes. It contributes not only to reduce transmission time but also to balance energy consumption of nodes. In this work, we evaluate the performance of EMP through theoretical and simulation-based analysis and compare the performance with other existing pipelines. The results show that EMP outperforms the existing protocols in terms of transmission time and energy efficiency, and then the improved performance of EMP can be maintained regardless of network environments such as link quality, hop counts, and network density.