The expressed CH925 was aggregated into inclusion bodies (IB) in E.coli cytoplasm. The IBs were isolated by centrifugation and sonication. CH925 were refolded and reoxidateo in a glutathione redox system following denaturation of the IBs in 7mol/L guanidine hydrochloride. The specificactivities of IL2 and IL6 assayed by CTLL-2 and 7TDl cell line were 2.2×10⁶U/mg and 2.3×10⁸U/mg, respectively,following renaturation. The renatured CH925 was chromatographed through DEAE-Sepharose 6B column and Sephacryl and column. The active fractions were pooled and applied to HPLC with reversed-phase C-18 column, while CH925 was eluted through 10%-70% acetonitrile gradient. It showed only one pratein peak and SDS-PAGE confirmed that the purified CH925 was almost homogeneous.