The invention discloses a green orange alkaloid extract with a function of preventing and treating asthma and a preparation method of the green orange alkaloid extract. It is found that the green orange alkaloid extract has a significant improvement function on the asthma caused by histamine, effectively alleviates the increase of airway resistance and decrease of dynamic lung compliance in asthmatic guinea pigs, inhibits the increase of eosinophilic granulocytes, reduces the content of IgE, IL-4 and IL-5 in the serum and reduces the infiltration degree of inflammatory cells in the lung tissue; the orange alkaloid extract has no significant effect on the weight of the guinea pigs and has functions of auxiliary protection, prevention and treatment on the asthma.