Objective To develop a film infiltration method with colloidal gold particle to measure salivary IgA and evaluate the mucous immunological function in HIV-infected patients.Methods The total IgA and IgA 1 in saliva of HIV-infected patients or HIV carrier were measured by colloidal gold fiter infiltration and the ratio of IgA 1/IgA was calculated.The results were compared with those of health individuals.Results The results of fiter infiltration method were correlated with those of nepheloturbidimetry (r=0.918).The salivary IgA and ratio of IgA 1/IgA in HIV patients were significantly lower than those of health individuals (P<0.001).The salivary IgA of HIV carriers was increased (P<0.001),but the ratio of IgA 1/IgA was decreased (P<0.01).Conclusion Colloidal gold fiter infiltration may be a suitable quantitative method for rapid determination of salivary IgA and its subclasses.The mucosal immune function decreased in HIV patients.