With the development of quantum computers, traditional encryption algorithms are seriously threatened. In order to combat with quantum attacks, homomorphic encryption technology has received attention increasingly. Among them, the ring-learning with error (R-LWE) encryption scheme has the advantages of high encryption efficiency and simple hardware implementation as well as huge potential in hardware encryption. This paper proposes and implements an RLWE encryption and decryption circuit structure, which uses Fermat number transforms (FNT), memory access optimization and time division multiplexing methods. The results show that under the equivalent security parameter set, in the terms of the encryption and decryption function, The hardware resource efficiency of the RLWE encryption and decryption circuit can reach 6.01 and 12.03 respectively.