Objective To develop plaque assay for SARS virus, in order to provide a reliable means for SARS research. Methods SARS virus BJ 01 strain in various dilutions was inoculated to Vero E6 cells, the cells were then covered with nutritious agar. The titers of the plaque were measured by Dullbecco R method. Results The plaque of SARS virus appeared on the third day after the cell cultures infected with virus. The plaque was round in shape, 2.5-3 mm in diameter. Conclusion The plaque assay developed in present study was stable and regular, and it could be used in SARS research.