A micro-magnetic detecting method includes the steps of: detecting a magnetic induction intensity along a first direction on a surface of a detected object to generate a detection signal, determining whether an amplitude of the detection signal is an anomalous value at a first position of the surface of the detected object, wherein the anomalous value is a value which is inconsistent with a linear value of the detection signal at the first position, and the linear value is a value that satisfies a linear relationship of the detection signal, and determining there is a defect at the first position of the detected object in case that the amplitude of the detection signal is the anomalous value. Accordingly, it detects the magnetic induction intensity on the surface of the detected object so as to detect its surface and internal defects when it remains in its original status.