The sensitive and rapid detection of foodborne pathogens is of great significance to global public health security. Here, with two-dimensional nanomaterial MnO2 NSs as the capture antibody imitator and signal reporter molecules, based on its enzyme-catalyzed signal amplification capability, a label-free, dual-signal output immunochromatographic biosensor was constructed to achieve the sensitive detection of S. enteritidis. The capture antibody imitator of MnO2 capture probe shows an outstanding capture ability, forming a stable immune complex with S. enteritidis. As an in-situ catalytic amplification colorimetric signal trigger, MnO2 NSs exert oxidase-like enzyme activity and obtain satisfactory detection sensitivity. It is worth noting that the proposed dual-signal ICA has high analytical performances for S. enteritidis during the concentration range of 103-107 cfu mL−1 both in standard bacterial solutions and food matrixes.