Aiming at the problems of lacking data confidentiality protection, weak computing ability and limited bandwidth in real-time data transmission of power wireless sensor networks, an ultra-lightweight stream encryp- tion scheme was proposed. It consists of three parts: key creation, encryption and decryption. Furthermore, a data encryption transmission protocol for power wireless sensor networks was designed. Besides, the key implementa- tion code and simulation were given. The simulation results show that compared with other algorithms, the effi- ciency is greatly improved and the difficulty of implementation is lower, and it is suitable for the secure trans- mission of data in the application scenarios where the computing power of power wireless sensor network devices is relatively weak.