The invention discloses a sensitive probe as well as a preparation method and a method for detecting salmonella enteritidis by virtue of the sensitive probe, relates to a probe, a preparation method and application of the probe, and aims to solve the problems of high cost, instability, high deactivation rate of an antibody and poor sensitivity of an existing probe. The sensitive probe is prepared from antibiotics and a signal carrier. The preparation method comprises the following steps: 1, preparing yellowish-brown emulsion; 2, preparing a carboxylated immunomagnetic bead; 3, preparing an activated magnetic microsphere; 4, adding a resuspension solution for storage. The method for detecting the salmonella enteritidis by virtue of the sensitive probe comprises the following steps: 1, preparing an immunochromatographic test strip for the salmonella enteritidis; 2, mixing liquid to be detected and the sensitive probe for incubation, adding dropwise a mixed solution onto a sample pad of the immunochromatographic test strip for the salmonella enteritidis, performing reaction for 10 minutes, and reading a result. According to the sensitive probe, the preparation method and the detection method, only one antibody is struck on a nitrocellulose membrane for direct detection, so that the cost is greatly reduced, and simplicity and convenience are achieved; the sensitive probe, the preparation method and the detection method are applied to detection of the salmonella enteritidis.