An immobilization method using a sulfhydrylated monoclonal antibody (mAb) on the gold surface of a microcantilever immunosensor was developed for label-free detection of taxol. The sulfhydrylated anti-taxol mAb was synthesized. Then it was immobilized on the gold surface of the microcantilever. The deflection of the microcantilever corresponding to different taxol concentrations was real time monitored by optical lever technique. The activity of the anti-taxol mAb before and after sulfhydrylation, and the binding of the sulfhydrylated anti-taxol mAb on the gold surface of the microcantilever were evaluated by non-competitive Enzyme-Linked Immunosorbent Assay (ELISA). The limit of detection is 1 ng/mL and the method was used for detection of taxol in human plasma sample.