Two new sesquiterpenoids, vernobockolides A (1) and B (2), along with five known ones, piptocarphin C (3), piptocarphin F (4), piptocarphin A (5), hirsutolide (6), and β-d-glucopyranosyl taraxinic ester (7), were isolated from the aerial part of Vernonia bockiana. Their structures were determined by spectroscopic analysis, especially 2D NMR. Among them, compounds 2-6 showed strong cytotoxic activities against mouse lymphoid tumor cell line P388 with the IC50 values of 1.81, 1.32, 0.77, and 0.73 μM, respectively.