In view of the shortcomings of limited terminal battery capacity and low energy efficiency in the existing research on CR-NOMA (cognitive radio non-orthogonal multiple access) networks, a relay was used to assist users in transmission, and a method of simultaneous transmission of wireless information and energy was introduced. Under the constraints of user service quality and minimum energy capture, the sub-user transmission energy efficiency expression was derived. The non-convex objective function was transformed into three convex single-objective problems of optimizing relay transmission power, relay power allocation and receiver power allocation by fractional programming method. Using function monotonicity, golden section algorithm, Lagrangian dual algorithm and multi-objective joint optimization algorithm for optimization, the global optimal solution was obtained to maximize the transmission energy efficiency of the secondary user system. The complexity of the adopted algorithm was analyzed.The simulation results show that compared with the traditional OMA (orthogonal multiple access) scheme, while the system spectrum utilization was improved, the sub-user transmission energy efficiency has been improved by 47%.