Human SOD cDNA was cloned and constructed an expression plasmid with high sufficient and stabilility expression in E. coli. The rhSOD cDNA was amplified by RT-PCR with the template of the total RNA extracted from human liver tissue. The expression plasmid, pLY-4/rhSOD, containing rhSOD cDNA, was transformed into the E. coli JF1125. The sequence of the cloned rhSOD cDNA was identified with the reported data. The expression level reached to more than 68% of total bacteria proteins; The technology for protein renature and purification was efficiency and fast. The purity of the final products reached more than 98%. The value of bioactivity was determined as 2529 u/mg. This study gave enough support for production of rhSOD by biotechnology.