The disclosure provides a transformer fault comprehensive diagnosis system based on a fuzzy association rule. The system includes a transformer fault type diagnosis module, a transformer fault location diagnosis module, and a transformer fault comprehensive diagnosis module based on case-based reasoning. The disclosure also provides a transformer fault comprehensive diagnosis method based on a fuzzy association rule. The diagnosis system diagnoses the fault type, the fault location and the fault cause of a transformer, can help the field staff to complete discrimination, and is suitable for the diagnosis of a variety of transformer faults.