The present invention relates to a detection circuit for detecting coil abnormality of a DC fan motor, which is applied to a fan. The detection circuit comprises at least one detection unit and a processing unit. The detection unit is used to detect and receive the voltage signal at the center point of the coil set of the fan stator and perform a clamping process and a inverting process on the voltage signal to generate an inverted voltage signal such that the processing unit compares the inverted voltage signal with a predetermined value and determines to generate a notifying signal to a remote device. Thus, the effect of effective real-time monitoring the fan can be achieved.