▎ 摘　　要

NOVELTY - Method for preparing nanocomposite, involves adding thionine to graphene solution, subjecting the obtained mixture to ultrasound processing to obtain thionine-graphite compound, adding the thionine-graphite complex to chitosan solution, preparing thionine-graphite nano-granule wrapped by chitosan, dispersing the obtained granule, mixing the obtained granule with hexachloroplatinic acid, and dropping or adding sodium borohydride to the obtained mixture to obtain the molybdenum-chitosan-thionine-graphite nanocomposite. USE - The method is useful for preparing nanocomposite which is used in electrochemical immune detection method for detecting protein, preferably tumor marker protein chosen from gastrin-releasing peptide precursor, neuron-specific enolase, cytokeratin 19 fragment (CYFRA21-1), alpha -fetoprotein (AFP), abnormal prothrombin, carcinoembryonic antigen (CEA), cancer antigen (CA) 242, CA125, CA199, CA153, CA724, CA50, free-prostate-specific antigen (PSA), total-PSA, beta -human chorionic gonadotropin (hCG), squamous cell carcinoma antigen (SCCA), and 2 microglobulin, preferably abnormal prothrombin (all claimed). ADVANTAGE - The nanocomposite has excellent specificity and sensitivity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) nanocomposite prepared by the above-mentioned method; and (2) electrochemical immune detection method, involves preparing the nanocomposite, coupling the nanocomposite with to-be-tested protein antibody, labeling the obtained product using horseradish peroxidase enzyme, adding pretreated glassy carbon electrode to the antibody solution, sealing the obtained product to remove non-specific binding site to obtain an electrode, combining the electrode with protein (to-be-detected), obtaining working electrode using linear scanning voltammeter electrochemical detection, drawing standard curve of working electrode and standard electrode, incubating the electrode and the sample, performing electrochemical luminous test, measuring electrochemical peak current intensity of the sample, and reading the corresponding concentration of the protein from the standard curve.