This invention relates to a method for inducing synthesis of triterpenoids to increase the content of triterpenoids in the mushroom. The mushrooms are placed in a temperature controlled room to perform high temperature and high humidity fermentation. After the mushrooms have browning reaction, also called maillard reaction, the objective of increasing the content of triterpenoids in the mushroom is completed.本發明係為一種利用誘導三萜合成的方法將菇蕈內之三萜類含量提升。其係將菇蕈置於溫控室內進行高溫高溼發酵作用,當菇蕈類發生褐變反應後(又稱梅納反應Maillard reaction),即完成菇蕈類內的三萜類含量提升之目的。