The invention relates to a nondestructive detection circuit and method for insulation resistance of a high-voltage battery energy storage system. The circuit comprises a resistance network, a voltage test differential amplification circuit, a high-frequency filter circuit, a signal isolating circuit, an AD conversion circuit and a data processing unit which are connected in sequence. According to the technical scheme, the nondestructive detection circuit and the method are used for detecting positive pole grounding faults and negative pole grounding faults of an energy storage battery system. The grounding faults of the high-voltage battery energy storage system are detected fast, various leakage currents in the use process are handled, meanwhile, the insulation performance of the system is prevented from being damaged in the detection process, and the safety of the battery energy storage system is improved.