Abstract: Objective To express the SARS-CoV S2 protein in E coli and to study on its immune characteristics preliminarily.Methods SARS-CoV S2 gene was cloned and the GST-S2 fusion protein was expressed in E coli.The activity of the expressed GST-S2 fusion protein was identified by Western blot and enzyme linked immunosorbent assay(EL ISA).Results Prokaryotic expressed GST-S2 fusion protein could bind the GST polyclone antibody and an 85 KD immune band could be detected.Expressed GST-S2 protein had response to convalescent serum from SARS patients,but not to control serum.Conclusion The obtained GST-S2 protein could be provided for the study on the infection process of host cells by SARS2CoV and the preparation of the recombination vaccine.