The article studied the resonance light scattering of protein red alizarin with the simple fluorescence spectrophotometer first.In Britton Robinson butter of 4.10,the red alizarin combined with proteins by intermolecular forces to form complexes,causing an enhance of resonance light scattering(RLS) at maximum wavelength of about 360nm.Based on the enhancement of resonance light scattering a novel method for the determination of proteins using red alizarin was developed.Though it affected by the limit of the filter of spectrophotometer the experiment used the wavelength of incident light doesn’t lie in the maximum wavelength,the method has better linear range within 0~10.0μg/ml,determination limits being 0.04μg/ml.The method had been used to determine total proteins in human serum samples and with accuracy and torelant to many foreign substance.