Abstract: The new reagent named 5,7-dichlorocalix(4)areneazo aminoquinoline (abbreviated as CCAQ) was synthesized and its molecular structure characterized by IR-spectrometry and elementary analysis.It was found that in a borate buffer medium of pH 10.8 and in the presence of Tween-40 and CTMAB,a stable complex having its mole ratio of 1 to 1 was formed between CCAQ and Ni(Ⅱ),with its absorption maxima at the wavelength of 620 nm.The molar absorptivity of the complex was found to be 1.83×105L·mol-1·cm-1.Beer′s law was obeyed in the range of 0.1-8.0 μg of Ni(Ⅱ) per 25 mL of solution.The absorbance of the colored complex in the medium of the reaction system was kept stable for at least 8 h.In its application to the analysis of aluminum alloys,RSD′s found from the analytical results were less than 3.5%,and the recoveries were in the range of 98%-101%.