A method for the determination of human immunoglobulin G(IgG) based on a colloidal gold label by fluorospectrophotometry was developed.The sandwich immunoreaction among goat-anti-human IgG,human IgG and goat-anti-human IgG labeled with colloidal gold nanoparticles was applied in this experiment.First,a sandwich im-munocomplex was formed on the surface of 96 well clear polystyrene high bind stripwell(tm) microplate.After the formation of the sandwich immunocomplex,a solution was added to dissociate the immunocomplex at room temperature.Then the solution of each well was transferred into the corresponding test tube.Thirdly,the rhodamine B solution was injected into each test tube.The rhodamine B chloraurate was extracted into ether that was measured with a spectrofluorometer.The experimental results indicate that the fluorescence intensity increased with the increase of human IgG concentration.The fluorescence intensity of rhodamine B chloraurate at 570 nm was proportional to the logarithm of human IgG concentration in a range from 10 to 5×10~5 ng/mL.It was shown that the determination of human IgG was easily made with the proposed fluorospectrophotometry.