The McEliece public key cryptosystem is known for its resistance to quantum attacks. However, its application potential remains limited due to challenges such as large key size and low coding efficiency. In this paper, we proposed a McEliece public-key cryptosystem based on cyclic codes to reduce the key size. The matrix generated by the Goppa codes is replaced with the matrix generated by the cyclic code in encoding, the private key matrix is transformed into the row vector of the generator polynomial. Performance evaluations and security analysis reveal that the refined system retains commendable coding efficacy and security with a condensed key space.