An in vitro method of screening of a therapeutic agent for preventing and treating Alzheimer's disease comprising identifying a substance inhibiting binding between amyloid-β (Aβ) and Fcγ receptor IIb (FcγRIIb), or inhibiting intracellular translocation of Aβ and FcγRIIb after binding, wherein - the identifying a substance inhibiting binding between amyloid-β (Aβ) and Fcγ receptor IIb (FcγRIIb) comprises: i) adding a compound to be tested before, after or during binding between all or part of FcγRIIb and all or part of Aβ; ii) measuring a binding degree between all or part of FcγRIIb and all or part of Aβ; and iii) determining whether the compound reduces binding between all or part of FcγRIIb and all or part of Aβ in comparison with a control, or i) contacting all or part of FcγRIIb with a compound to be tested; ii) measuring a binding degree of the compound to all or part of FcγRIIb; and iii) determining whether the compound has high binding affinity to all or part of FcγRIIb in comparison with a control, or i) treating a brain cell culture with a compound to be tested; ii) measuring an expression level of FcγRIIb in the brain cell culture; and iii) determining whether the compound inhibits FcγRIIb expression in comparison with a control, or i) treating a cell line expressing an FcγRIIb chimeric protein with Aβ and a compound to be tested; ii) measuring activity of the FcγRIIb chimeric protein; and iii) determining whether the compound inhibits the activity of the chimeric protein in comparison with a control, and - the identifying a substance inhibiting intracellular translocation of Aβ and FcγRIIb after binding comprises: i) adding a compound to be tested before, after, or during binding between all or part of Aβ and all or part of FcγRIIb; ii) measuring a binding degree between all or part of FcγRIIb and all or part of Aβ; iii) determining whether the compound reduces binding between all or part of FcγRIIb and all or part of Aβ in comparison with a control; and iv) determining whether the compound inhibits intracellular translocation of all or part of Aβ and all or part of FcγRIIb. - the identifying a substance inhibiting binding between amyloid-β (Aβ) and Fcγ receptor IIb (FcγRIIb) comprises: i) adding a compound to be tested before, after or during binding between all or part of FcγRIIb and all or part of Aβ; ii) measuring a binding degree between all or part of FcγRIIb and all or part of Aβ; and iii) determining whether the compound reduces binding between all or part of FcγRIIb and all or part of Aβ in comparison with a control, or i) contacting all or part of FcγRIIb with a compound to be tested; ii) measuring a binding degree of the compound to all or part of FcγRIIb; and iii) determining whether the compound has high binding affinity to all or part of FcγRIIb in comparison with a control, or i) treating a brain cell culture with a compound to be tested; ii) measuring an expression level of FcγRIIb in the brain cell culture; and iii) determining whether the compound inhibits FcγRIIb expression in comparison with a control, or i) treating a cell line expressing an FcγRIIb chimeric protein with Aβ and a compound to be tested; ii) measuring activity of the FcγRIIb chimeric protein; and iii) determining whether the compound inhibits the activity of the chimeric protein in comparison with a control, and i) adding a compound to be tested before, after or during binding between all or part of FcγRIIb and all or part of Aβ; ii) measuring a binding degree between all or part of FcγRIIb and all or part of Aβ; and iii) determining whether the compound reduces binding between all or part of FcγRIIb and all or part of Aβ in comparison with a control, or i) contacting all or part of FcγRIIb with a compound to be tested; ii) measuring a binding degree of the compound to all or part of FcγRIIb; and iii) determining whether the compound has high binding affinity to all or part of FcγRIIb in comparison with a control, or i) treating a brain cell culture with a compound to be tested; ii) measuring an expression level of FcγRIIb in the brain cell culture; and iii) determining whether the compound inhibits FcγRIIb expression in comparison with a control, or i) treating a cell line expressing an FcγRIIb chimeric protein with Aβ and a compound to be tested; ii) measuring activity of the FcγRIIb chimeric protein; and iii) determining whether the compound inhibits the activity of the chimeric protein in comparison with a control, and - the identifying a substance inhibiting intracellular translocation of Aβ and FcγRIIb after binding comprises: i) adding a compound to be tested before, after, or during binding between all or part of Aβ and all or part of FcγRIIb; ii) measuring a binding degree between all or part of FcγRIIb and all or part of Aβ; iii) determining whether the compound reduces binding between all or part of FcγRIIb and all or part of Aβ in comparison with a control; and iv) determining whether the compound inhibits intracellular translocation of all or part of Aβ and all or part of FcγRIIb. i) adding a compound to be tested before, after, or during binding between all or part of Aβ and all or part of FcγRIIb; ii) measuring a binding degree between all or part of FcγRIIb and all or part of Aβ; iii) determining whether the compound reduces binding between all or part of FcγRIIb and all or part of Aβ in comparison with a control; and iv) determining whether the compound inhibits intracellular translocation of all or part of Aβ and all or part of FcγRIIb.