The invention discloses a pharmaceutical composition for preventing and treating livestock/poultry virus diseases. The pharmaceutical composition is a preparation prepared from the following active pharmaceutical ingredients: isatis root and paulownia leaf. The drug effect experiment result indicates that the combination of the paulownia leaf and isatis root has obvious treatment effects on livestock/poultry virus diseases and can greatly lower the mortality of sick animals. Besides, the combination of the paulownia leaf and isatis root greatly has much higher drug effects than the independently used isatis root under the condition of the same dose, and the paulownia leaf and isatis root have the synergistic effect.