Abstract: Being the key algorithm of SM2,the special elliptic curve cryptography algorithm presented by OSCCA, modular multiplication defines the system's overall performance.One of the most efficient and widely used modular multiplication algorithms is Montgomery modular multiplication algorithm.This paper presents a new hardware architecture to realize modular multiply in dual field (GF (p) and GF (2^m)) based on the improved dual -field Montgomery modular multiplication's algorithm.A new kind of Wallace tree multiplier is also presented in this paper.This multiplier could realize higher performance with less computing resource and lower timing consumption due to the reasonable arrangement and reusing of modules.One complete operation of 256 bit dual-field modular multiplier can be finished in 0.34μs.