In this paper, the color reaction between titanium and Arsenazo Ⅲ is studied.The purple coloration formed in sulfuric acid medium may be used for detection of titanium (Ⅳ).The limit of identification and dilution limit are found to be 0.25 μg Ti and 1:200,000 respectively.Many ions interfere with the reaction.Their limiting proportions has been found experimentally.The interference caused by foreign ions can be easily eliminated by masking and/or by simple separations.