Aluminium citrate was widely used in water shut-off, profile control and oil displacement operation in oilfield. It was necessary to determine aluminum content during the process of producing and using. But the related determination method hadn’t been found in industrial standard or research report. Citric acid would interfere with the determination of aluminum when routine complexometric titration was adopted. The content of aluminum in aluminium citrate could be determined precisely by the way of complexometric titration if the interfere produced by citrate ions was removed by preprocessing with acids. The twelve hydrated aluminum potassium sulfate samples containing citric acid were treated with sulphuric acid and nitric acid whose volume fraction was more than 50% for digestion in the room. Xylenol orange had been put into the samples before titrated. Then an appropriate amount of sodium hydrate solution was added into the test solution whose color changed from yellow to purple. Finally 8% nitric acid solution was used for changing the color of test solution to light yellow. The pH value was between 5.5 and 6.0. Titration end point was clear, and the absolute relative error was less than 1%. The recovery rate with standard sample ranged from 99.46% to 100.28%, and the absolute value of relative error for every determination was less than 2%, which showed good parallelization and had solved the problem of controlling product quality of aluminium citrate timely and effectually.