Objective:To explore the mechanisms of 5HT on the airway remodeling of bronchial asthma in guinea pigs.Methods:50 guinea pigs were divided into 5 groups:normal group(A group),asthma model group(B group),continued asthma model group(B_1 group),5-HT group(B_2 group),anti-5-HT group(B_3 group).Remodeling models of asthma were established with ovalbumin.Results:In B group,concentration of 5-HT in serum and thicknesses of airway mucosa,base membrane,smooth muscle were significantly increased compared with A group(P0.05,0.01).In B_1 group,concentration of 5-HT and thicknesses of airway walls were significantly increased compared with B group(P0.05,0.01).Thicknesses of airway walls in B_2 group were greater than those of B_1 group(P0.05).Thicknesses of airway walls in B_3 group were smaller than those of B_1 group(P0.05).With the aggravation of airway remodeling,lungs/weight and brain/weight were upward.Conclusion:5-HT is one of the mechanisms of the airway remodeling of bronchial asthma in guinea pigs.