Corydalis Rhizoma (CR) is a commonly used traditional Chinese medicine for its potency in activating blood circulation and analgesia. In clinic, CR extracts or components are commonly used in the treatment of myocardial ischemia, rheumatism, and dysmenorrhea with different types of inflammation. However, due to different mechanism of pain and inflammation, the anti-inflammatory property of CR has not been fully revealed. Here, the major chromatographic peaks of CR extracts in different extracting solvents were identified, and the anti-inflammatory activities of CR extracts and its major alkaloids were evaluated in LPS-treated macrophages by determining expressions of proinflammatory cytokines, IB and NF-B. The most abundant alkaloid in CR extract was dehydrocorydaline, having >50% of total alkaloids. Besides, the anti-inflammatory activities of dehydrocorydaline and its related analogues were demonstrated. The anti-inflammatory roles were revealed in LPS-treated cultured macrophages, including (i) inhibiting proinflammatory cytokines release, for example, TNF-, IL-6; (ii) suppressing mRNA expressions of proinflammatory cytokines; (iii) promoting IB expression and suppressing activation of NF-B transcriptional element; and (iv) reducing the nuclear translocation of NF-B. The results supported that dehydrocorydaline was the major alkaloid in CR extract, which, together with its analogous, accounted the anti-inflammatory property of CR.