Objective To investigate whether quercetin can inhibit airway inflammation in asthmatic mice and its specific molecular mechanism. Methods A mouse model of bronchial asthma was established by intraperitoneal injection of ovalbumin (OVA). Thirty-six female BALB/c mice were randomly divided into 6 groups: control group (CON group), asthma model group (OVA group), low dose quercetin (LOW group), middle dose quercetin (MID group), high dose quercetin (HIGH group) and dexamethasone positive control group (POS group). The asthmatic symptoms were scored in mice, the levels of inflammatory mediators IL-4 and IL-5 in the supernatant of bronchoalveolar lavage fluid (BALF) were detected by enzyme-linked immunosorbent assay (ELISA), and the levels of microRNA-155 in lung tissues were detected by qRT-PCR. Results Compared with CON group, OVA group had higher asthma symptom score and higher expression of IL-4, IL-5 and microRNA-155 (all P?