This study is to investigate the treatment of YinQiaojiedu soft capsule for influenza virus A/PR8/34 (H1N1) infection.  The model of pneumonia was established by dropping influenza virus into the nose of normal mice, and the lung index and death rate were observed.  Real time RT-PCR and Western blotting technique were used to detect the virus load and the relative expression of M1 protein in lungs of mice on the 1st, 3rd, 5th and 7th day after infection.  The results showed that YinQiaojiedu soft capsule in 1 g·kg⁻¹ and 0.5 g·kg⁻¹ dose groups can decrease the lung index significantly on the 3rd, 5th and 7th day after being infected (P < 0.05, P < 0.01), and the number of death in the two groups of animals decreased significantly.  YinQiaojiedu soft capsule in 1 g·kg⁻¹ dose group can decreased virus load at each time point, and lower it in 0.5 g·kg⁻¹ dose group at the 3rd, 5th and 7th day (P < 0.05, P < 0.01).  YinQiaojiedu soft capsule can decrease the relative expression of M1 protein in lungs of mice, 1 g·kg⁻¹ and 0.5 g·kg⁻¹ dose groups are significantly lower in expression of M1 protein compared with model group at the 3rd and 7th day (P < 0.05, P < 0.01).  It can be concluded that YinQiaojiedu soft capsule exerts antiviral effects against influenza virus by downregulating expression of virus load and M1 protein.