It is taking hychroperoxides as masking agents, alumnium in titanium alloys was meascred with aluminon ammonium aurintri- carboxylate. The method successful to settle the interfering problem of titanium and other elements in traditional analysing method using separation by precipitation to smooth away them. The analysing procedure was sinplified and the analysing time was shortened to one se- cond. Relativelv satisfactory effects are obtained.