Severe mycoplasmal pneumoniae pneumonia in children is a serious respiratory disease with complex conditions and rapid progression， posing a serious threat to children’s health and life safety. Professor YAN Huimin believes that this disease can be treated according to stages from the perspective of pulmonary collateral disease. The overall treatment principle is mainly to “dissipate phlegm and dredge collaterals”. In the early treatment phase， the method of dispelling wind-evil and dredging collaterals was mainly adopted， while in the critical phase， the method of toxin removing and collaterals dredging was employed. Additionally， in the recovery phase， the method of benefiting qi， nourishing yin， and dredging collaterals was utilized to dispel evil and dredge the collaterals， thereby regulating and nourishing qi and blood. As a result， the occurrence of pulmonary sequelae can be reduced to yield satisfactory therapeutic efficacy.