Asthma is a complex chronic inflammatory disorder in the airway accompanying airway hyperresponsiveness, airway obstruction and airway wall remodeling. Alisma canaliculatum (AC) is a constituent of Cheong-Sang-Bo-Ha-Tang (CSBHT) which had been frequently prescribed to treat the respiratory disease in traditional Korean medicine. Here, we investigated the precise mechanism of the anti-inflammatory activity of AC extract using ovalbumin-induced mouse asthma model. AC extract administration improved the mouse AHR, and alleviated the thickened airway epithelium. These effects may mediate by the inhibitory effect of AC extract on nuclear factor kappa B (NF-${kappa}B$) activation. And the inhibitory effect regulated the inducible nitric oxide synthase (iNOS) expression at the transcription level. We determined the AC extract metabolites through UPLC/ESI-QTOF-MS and identified 10-O-methyl-alismoxide, 11-deoxyalisol C, 4-12-dihydroxyguaian-6,10-diene, alismol, alismoxide, alisol B, alisol B 23-acetate, alisol C 23-acetate, and alisolide. This study provides the full understanding about the anti-asthmatic effect of AC extract for the first time.