Embodiments of this application relate to the monitoring field, and disclose a method for monitoring an insulation monitoring circuit and a battery management system. In some embodiments of this application, the method for monitoring an insulation monitoring circuit includes: in a state in which a first switch and a second switch are closed and a third switch is open, obtaining a first electrical signal detected by a second monitoring module; and based on the first electrical signal and a voltage reference value between a positive electrode of a battery pack and a negative electrode of the battery pack, determining whether an insulation monitoring circuit is faulty; or obtaining a second electrical signal detected by a first monitoring module and a third electrical signal detected by a third monitoring module, and based on the second electrical signal and the third electrical signal, determining whether the insulation monitoring circuit is faulty.