Novel 3'-N-tert-butylsulfonyl analogues 10a-c of docetaxel were synthesized and their biological evaluation in cytotoxicity in vitro against several human tumor cell lines were presented. The biologically tested results showed that N-oxide pyridyl substituted10b-c had potent cytotoxicities against human tumor cell lines Eca-109, SKOV3, SMMC-7721, HCT-8, PC3, MCF-7, HeLa and KB.