The invention discloses a transformation-loss precision-measurement device including a remote master station (1) connected with a distribution and transformation monitoring terminal (2) in a power-distribution stage area through a GPRS. The distribution and transformation monitoring terminal (2) is wirelessly connected with a high-voltage electric-energy meter (4) through micro power. The distribution and transformation monitoring terminal (2) is connected with a low-voltage electric-energy meter (3) through an RS485. The transformation-loss precision-measurement device is capable of measuring stage-area transformer loss in a real-time and precise manner and is safe and durable.