Abstract: A power consumption monitoring device includes a sensor, a storage, and a processor. The sensor is configured to detect a power-consuming device quantity and a power consumption amount. The storage is configured to store the power-consuming device quantity and the power consumption amount. The processor is communicatively connected to the sensor and the storage. The processor is configured to calculate a power-consuming device idling indicator based on the power-consuming device quantity and the power consumption amount in a monitoring time interval, wherein the power-consuming device idling indicator is used for indicating a deviation status of the power-consuming device quantity and the power consumption amount. The processor is further configured to determine whether the power-consuming device idling indicator exceeds a warning threshold. In response to the power-consuming device idling indicator exceeding the warning threshold, the processor is further configured to generate a warning message.