To study the influences of different probes on the analytical sensitivity of immunochromatography assay(ICA),a traditional probe was prepared for the detection of 17β estradiol(17β E2),with magnetic nanoparticles(MNPs) to label 7 μg/mL 17β E2 monoclonal antibody(mAb,detection Ab).Meanwhile,a paired probe was prepared by using MNPs to separately label 5 μg/mL 17β E2 mAb and 5 μg/mL goat anti-mouse polyclonal antibody(pAb,the second antibody),and an indirect probe was prepared by using MNPs to label 14 μg/mL pAb.Then,three immunochromatography assays were established based on the three probes for the rapid detection of estradiol.The analytical sensitivities of three ICAs were compared by the 17β E2 detection.Results showed that the analytical sensitivities of ICAs based on traditional,paired and indirect probes for 17β E2 are 1,05,02 ng/mL,respectively.Among these three ICAs,the analytical sensitivity of indirect probe based ICA is the highest.Compared with the traditional and paired probes based ICAs,the detection limit of the indirect probe based ICA is 5 fold and 25 fold reduced,respectively.This study refreshes the conventional cognition toward the signal probe which is considered can only be prepared by using signal materials to label the detection Ab in the traditional immunochromatography assay,and provides a valuable reference for the rapid detection of other food safety hazard factors by immunochromatography assays.