Abstract: This article studies the encryption of electronic tag data in the core technology of the Internet of Things,the underlying scalar multiplication of elliptic curve encryption system is optimized, and proposes an improved PECC-NAF scalar multiplication algorithm to resolve the contradiction between the limited hardware resources and high security requirements of the RFID system. First, the NAF scalar multiplication method is used to reduce the hamming weight of the scalar. Then, through the task decomposition strategy and parallel structure, the scalar multiplication doubling operations and adding operation are performed in parallel. Finally, simulation experiments are carried out to verify the computational efficiency and security of this algorithm and compare it with other algorithms to prove the superiority of this algorithm. The experimental results show that compared with the traditional binary scalar multiplication algorithm, under 160-bit and 255-bit key lengths, using the scalar multiplication algorithm proposed in this paper can reduce the running time of the scalar multiplication algorithm to one-fifth and one-third of the original.