Abstract:In the medium of HCl, amido black 10B and human serum albumin can rapidly combine and produce blue complex at the room temperature, in the process of which the maximum absorption peak is at 598 nm. Beer’s law is basically obeyed within the range 4.0～20 μg/mL for human serum albumin with an apparent molar absorptivity of 2.07×106 L·mol-1·cm-1. This method gives a rather satisfactory performance in regards of sensitivity and selectivity and proves to be prompt and easy to handle..