Abstract: Benzyloxy cucurbit6uril (BnO₂CB6) was prepared and applied to fluorescence spectrophotometric determination of ceftriaxone sodium (CTRX) in its commercial preparations. In a B-R buffer solution of pH 6.5,BnO₂CB6 reacted with CTRX to form an inclusion complex (with mole ratio of 1 to 1), leading to photo-induced electron transfer in the system, and to obvious quenching of fluorescence. And it was found that when excited at 405 nm,fluorescence was emitted at 495 nm. Linear relationship was kept between magnitude of quenching of fluorescence intensity (ΔF) and concentration of CTRX in the range within 40 μmol·L^-1, with value of detection limit (3S/N) of 17 nmol·L^-1. Contents of CTRX in the samples of commercial preparations were determined by the proposed method, giving results in consistency with those given by HPLC and values of recovery found by standard addition were ranged between 98.0% and 101%, with values of RSD's (n=6) in the range of 3.0%-7.2%.