The invention discloses a system and method for determining the orientation of an anomalous body on the basis of circumferential electrode scanning and belongs to the technical field of tunneling geological ahead monitoring. The system comprises multiple circumferential electrodes, a constant-current driving circuit, a voltage measuring circuit, an extended cable, and an anchor pole. The multiple circumferential electrodes are uniformly distributed on a tunnel wall a certain distance behind the shield of a tunnel boring machine. The constant-current driving circuit successively supplies constant current to the circumferential electrodes. The voltage measuring circuit acquires corresponding shield voltage. The orientation of the anomalous body can be accurately determined by the analysis of the voltage on the shield. The system is simple in structure and easy to be manually operated.