Abstract: With SAF and cetyl--trimethyl ammonium bromide as the color--developingagent, for the determiation of uranium by photospectrometry, the maximum abso-rption peak occurs at 545 nm with a molar absorbance of 1.42×10~5. In the range0--25 g U per 50 ml, Beer's law is obeyed. CyDTA or EGTA etc. can be used asthe masking agent. The method can be used for the determination of trace amountof U in ores or waste liquid with high selectivity.