Abstract: 2-arylbenzothiazole derivatives containing electron-donating group labeled with ¹¹C or ¹²³I generally displayed high binding affinity for β-amyloid (Aβ) plaques, and were potential Aβ imaging agents. In the article, Aβ binding affinity parameter, lg K_i was used as dependent variable. Some molecule structure parameters obtained by structure optimization performed by Gaussian 98 for windows software were used as independent variable. The quantitative structure-activity relationship for twenty-eight 2-arylbenzothiazole derivatives as Aβ imaging agents was studied. The results indicate that lg K_i is correlated linearly with lg P, V_m, lg V_m, H_e and E_HOMO. Among them, the lipophilicity parameter (lg P) is a main factor of affecting Aβ binding affinity.