Abstract: The spectrophotometric determination of Al in high-level liquid waste is described. It is based on the formation of Al-CAS-DDMAA ternary complex. When the quantities of Fe. Ni, Cr. Mo. Mn are 200 times of Al. the quantity of Cu is 10 times of Al and the quantities of Ce. Ti, Zr are 5 times of Al, there is no influence on the determination of Al. The interference of U in serious. but can be elimi nated by extraction with 5% TOPO-CHCl_3. The absorption obeys the Beer law when the content of A is in the range of 0—2; 00 μg/10 ml. The precision is 1.6% and the recovcry is (98—102 )% for the synthetic sample. The precision is 3% and the additional recovery is (96—104)% for the sample from the high level liquid waste (HLLw).