Interleukin-6 (IL-6) is a multifunctional cytokine having a wide range of activity and has an impact on almost immune system cells such as B cells, T cells, hepatocytes, haematopoietic progenitor cells and cells of the central nervous system. IL-6 is produced by many different cell types and acts as pro- and anti inflammation cytokine. For effective expression in prokaryotic system, the cloned Vietnames chIL-6 gene was optimized using Optimum Gene Codon Optimization Analysis and the CAI was improved up to 0.89. The expression vector pGS-2la-chIL-6 containing optimized chlI-6 gene was successfully constructed. By induction with IPTG, recombinant chIL-6 protein was expressed in BL2l. The ELISA resuls and Polyacrylamid gel showed that expressed protein has molecular weight about 27 kDa, corresponding to theoretical calculation and mainly in inclusion bodies state.