Non-orthogonal multiple access (NOMA ) technology, which enables multiple users to share a single time-frequency resource block, has become a research hotspot of 5G multiple access technology. In order to maximize the energy efficiency of NOMA system, power allocation in non-orthogonal multiple access technology is studied, and a new NOMA power allocation scheme based on chaotic particle swarm optimization is proposed. The energy efficiency optimization model of NOMA is established, and the energy efficiency of the NOMA system is optimized by using the chaotic particle swarm optimization to distribute the power of the system. The simulation results show that the energy efficiency of the system is maximum when the power is 36dBm, and the iteration times are less and the energy efficiency is better than traditional particle swarm optimization algorithm.