The preliminary study revealed that the ethyl acetate eluate of Youngia japonica (YJ-E) could inhibit the expression of key proteins of p-p65, p-IκBα, p-IKKα/β, and p-AKT in LPS stimulated BV2 cell. Further phytochemical study led to the isolation of eight compounds from YJ-E, including one new sesquiterpene lactone. Their structures were elucidated by several spectroscopic data, and comparing the NMR data of known compound. In addition, all of the isolates were evaluated for the anti-inflammatory effect. As a result, compounds 3 and 4 distinctly attenuated the expressions of p-IκBα, p-p65, and p-AKT in LPS stimulated BV2 cell, respectively.