The invention relates to a set of a kit for detecting specificity platelet antoantibody by the combination of monoclonal antibody and nano-microspheres. The kit comprises each 3 ml of four types of monoclonal antibody-polystyrene nano-microspheres PBS solution, 6 ml goat-anti-human polyclonal antibody and PBS solution, wherein the four types of the monoclonal antibody-polystyrene nano-microspheres PBS solution are sealed by bovine serum albumin and are respectively connected with a monoclonal antibody SZ-2, a monoclonal antibody SZ-22, a monoclonal antibody SZ-21, a monoclonal antibody 7E3, and the concentration of polystyrene nano-microspheres is 2 mg / ml; the goat-anti-human polyclonal antibody is connected with fluorescein isothiocyanate and with the concentration of the goat-anti-human polyclonal antibody is 15 mug / ml. A detection process of the specificity platelet antoantibody comprises the following steps of: oscillating monoclonal antibody--microspheres and platelet lysis buffer sample for incubation; washing by PBS; adding the goat-anti-human polyclonal antibody connected with the fluorescein isothiocyanate; washing, re-suspending by the PBS; detecting on a flow cytometry to obtain average fluorescence intensity values of the four types of the nano-microspheres respectively; and confirming whether the specificity platelet antoantibody is positive or not according to a ratio of the obtained values to a basic contrast value of that of a healthy person, in order to provide foundation for early diagnosis of ITP. The detection has the advantages of simple process, high sensitivity and good specificity.