Twenty-one benzoylated phloroglucinol derivatives bearing homoadamantyl frameworks were isolated from the aerial parts of Hypericum sampsonii,including two new ones named hyperisampsins N and O(1 and 2).The structures of 1 and 2 were elucidated by extensive NMR and mass spectrometric analyses.Their absolute configurations were further determined by using TDDFT ECD calculations.Compounds 2,7,and 8 were evaluated for their cytotoxic activities against five human cancer cell lines,of which,2 and 8 exhibited significant cytotoxic activities toward HL-60 cell and moderate activities against others cell lines. Twenty-one benzoylated phloroglucinol derivatives bearing homoadamantyl frameworks were isolated from the aerial parts of Hypericum sampsonii, including two new ones named hyperisampsins N and O (1 and 2). The structures of 1 and 2 were elucidated by NMR and mass spectrometric analyzes. Their absolute profiles were further determined by using TDDFT ECD calculations. Compounds 2, 7 and 8 were evaluated as their cytotoxic activities against five human cancer cell lines, of which 2 and 8 exhibited significant cytotoxic activities toward HL-60 cell and moderate activities against others cell lines.