Cellulose synthases of advanced plants have multiple functional domains and belong to the family of glycosyltransferases. They act as the catalyst for the transfer of the β-1, 4-glucan, and construct the cellulose molecule which is one of the important cell wall components of advanced plants. Comparison among cellulose synthase family members within one species such as Arabidopsis demonstrated that there are two hypervariable regions (HVR) in its protein, The first HVR lies at the NH2-terminal (NHVR) and is rich of acidic amino acid residues. In this study, we cloned the NHVR coding sequence of the Boehmeria nivea (ramie) cellulose synthase gene (BnCesA1). Then the gene fragment was subcloned into the prokaryotic expression vector pQE-N1 after its 6×His tag in the right reading frame to construct pQE-N1-NHVR recombinant expression vector. After the confirmation of the expression of the fusion protein His-tag-NHVR by western-blotting, the expression conditions had been optimized using orthogonal array testing in E. coli BL21(DE3). The results showed that the optimal combination of small-scale expression conditions is: colony No. 2, with concentration of IPTG at 0.1 mmol/L, inducing time for 4 h and temperature at 37℃. Altogether, our results would benefit the subsequent purification of His-tag-NHVR fusion protein and the preparation of its antibody, and support the further study to regional functions of BnCesA1 and its tissue specific functions in ramie.