Abstract: The rbcL(large subunit of ribulose-1,5-bisphosphosphate carboxylase/oxygenase) gene of ephemeral plant Eremopyrum orientale L.was amplified from the genomic DNA and the correct gene sequence was registered in GenBank(Accession No.FJ346562).The rbcL gene was cloned into prokaryotic expression vector pGEX4T-1(harbored with gene encoding GST and will form a fusion protein with foreign gene) and eukaryotic expression vector pcDNA3,and then expressed in the BL21(DE3) and mouse,respectively.The expressed RBCL protein was detected by Western blot.The results showed that the ORF of rbcL included 1431 nucleotides and encoded 476 putative amino acids.It shares 99.86% homology with that of Eremopyrum triticeum.The fusion protein GST-RBCL with the size of 82 kD was expressed in inclusion body in BL21(DE3);the rbcL gene was shown being transcribed in the mouse liver by RT-PCR analysis.Western blot results showed that the purified RBCL was able to specifically bind to its antibody.These preliminary results would provide evidence for further immunohistochemistry assay in E.orientale.