Abstract: OBJECTIVE To establish a catalytic spectrophotometric method for determination of trace cisplatin injection. METHODS A catalytic spectrophotometric method based on the catalytic effect of platinum on the oxidation of tribromochlorophosphonazo 3-(2, 4, 6-tribromophenylazo)-6-(4-chloro-2-phosponophenylazo)-4,5-dihydoxynaphthalene-2,7- disufonic acid with KBrO3 in acidic medium had been proposed for the determination of trace cisplatin. The fading reaction was performed directly in an aqueous solution and the optimal conditions were given. RESULTS The calibration curves were linear over the concentration range of 3-24 ng·mL^-1 and the average recoveries of cisplatin were 99.3%, the RSD was 1.24%(n=3). CONCLUSION The catalytic spectrophotometric method is simple, rapid and sensitive, and could be used for the determination of cisplatin injection.