A dicistronic expression vector in E.coli has been constructed. The vector contains glutathione S-transferase (GST) gene as the first cistron, followed successively with translational enhancer, SD sequence, stop codon, start codon and multiple restriction enzyme sites for cloning(MCS).3'-terminal framgents of human bone morphogenetic protein (hBMP)gene 2A and 3 were inserted into the MCS respectively. After induction, un fused hBMP2A and hBMP3 expressed and occupied 10% and 15% of the total cell protein respectively. The GST gene in the plasmids were further shortened from 660 by to 206 bp. The expression level of hBMP2A and hBMP3 were double by the plasmids containing short GST gene as compared to that of the corresponding plasmids with large GST gene.