To study the pharmacological effects of Reduning Injection on parainfluenza virus pneumonia by different means of administration in immature mice，and to provide the reference for clinical medication.Methods:Young ICR mice were randomly grouped according to body weight class，including a normal group，a model group，a positive control group，and a Reduning Injection administration control group.Reduning atomized inhalation administration 20 min，10 min，5 min and 2.5 min groups.The parainfluenza virus was used for infection model of pneumonia in young mice.The lung index，lung index inhibition rate，lung tissue viral load，lung pathology score and other indicators were used to evaluate pharmacological effects of the different administration methods of Reduning Injection in treating parainfluenza virus pneumonia in young mice.Results:All the 4 groups of Reduning aerosol inhalation administration could reduce the lung index，viral load，alleviate the pathological damage of lung tissue.Compared with the model control group，there were significant differences(P<0.05) between the aerosolized inhalation administration group for 20 min.Conclusion:Reduning aerosol inhalation administration for 20 minutes has a significant therapeutic effect on viral pneumonia in mice caused by parainfluenza virus infection，and is better than the injection administration group.