This study is aimed to investigate the effect of Xilingjiedu capsule (XLC), one of a preparation of traditional Chinese medicine, on influenza A (H1N1) virus as well as its preliminary mechanism. The median cell mortality (TC50) to A549 cells and half effective inhibition concentration (IC50) of influenza A (H1N1) virus of XLC were determined by MTT assay. Reed-Muench method was used to calculated the 50% tissue culture infective dose (TCID50) of H1N1 virus to A549 cells. In mechanism research, the mRNA expression levels of MyD88, TLR4, TLR7 and TRAF6 and the protein expression level of MyD88 were detected by using RT-PCR and Western blot, respectively. The results suggested that XLC showed good anti influenza A (H1N1) virus activity. The antiviral mechanism of XLC was related to the Toll-like signaling pathway. It could drown regulate the mRNA expression level of MyD88 and TLR4 and the protein level of MyD88. This research provides reference for the application of XLC in anti influenza virus.