Abstract: In the Clark-Lubs buffer medium of pH 1.52,a compound complex was rapidly formed between fast green and serum protein under room temperature,with its absorption maximum at the wavelength of 670 nm.Based on this fact and by using the flow injection technique,a method of FI-photometric determination of serum albumin was proposed.Linear relationship between values of absorbance and concentration of serum albumin was kept in the range of 5-110 mg·L-1,with the detection limit (3S/N) of 0.52 mg·L-1 (for BSA) and 0.41 mg·L-1 (for HSA).In the analysis of samples of human urine and human serum,results obtained by this method was in consistency with the results found by the method of coomassie brilliant blue G-250.