In this study, we have evaluated four different 21-nt duplexes of small interfering RNA (siRNA-469, siRNA-852, siRNA-1802 and siRNA-1806) that specifically target the ORF2 gene of human astrovirus (HAstV) in inhibiting HAstV capsid protein expression in transfected BHK-21 cells. Furthermore, fluorescence analysis, real-time quantitative PCR (RT-qPCR) and western blot assays showed that pGPU6/GFP/Neo-shRNA inhibits ORF2 gene expression in Caco2 cells. The results indicate that siRNA/shRNA-469 and siRNA/shRNA-1802 can interfere with capsid protein expression in cell culture, and this provides a powerful tool for the study of HAstV gene functions and the biological properties of the capsid protein.