A smart identifying apparatus portable for a user to carry among different regions, comprising: a motion detecting circuit, configured to detect motions of the user; a communicating or communication circuit, having an effective wireless communication distance, configured to communicate with an Internet of Things, IOT, gateway via a wireless communication protocol in the effective wireless communication distance, such that the IOT gateway is capable of determining if the communication circuit is within the effective wireless communication distance corresponding to the IOT gateway, wherein an IOT apparatus is informed to perform a corresponding operation based on a predetermined rule if the IOT gateway determines that the communication circuit is in the effective wireless communication distance corresponding to the IOT gateway; a processing circuit, configured to compare a user motion detected by the motion detecting circuit with a predetermined motion rule, and configured to decide if the communication circuit is controlled to actively generate a signal to attempt to communicate with the IOT gateway according to the comparing result; and the communicating circuit is configured to enter a power saving mode if the communicating circuit does not attempt to communicate with the IOT gateway, characterized in that: the smart identifying apparatus further comprises a battery circuit, wherein the processing circuit is configured such that, if the battery circuit detects that a power is lower than a predetermined value, the processing circuit can set a rule for the communicating circuit to attempt to communicate with the IOT gateway according to the power. a motion detecting circuit, configured to detect motions of the user; a communicating or communication circuit, having an effective wireless communication distance, configured to communicate with an Internet of Things, IOT, gateway via a wireless communication protocol in the effective wireless communication distance, such that the IOT gateway is capable of determining if the communication circuit is within the effective wireless communication distance corresponding to the IOT gateway, wherein an IOT apparatus is informed to perform a corresponding operation based on a predetermined rule if the IOT gateway determines that the communication circuit is in the effective wireless communication distance corresponding to the IOT gateway; a processing circuit, configured to compare a user motion detected by the motion detecting circuit with a predetermined motion rule, and configured to decide if the communication circuit is controlled to actively generate a signal to attempt to communicate with the IOT gateway according to the comparing result; and the communicating circuit is configured to enter a power saving mode if the communicating circuit does not attempt to communicate with the IOT gateway, characterized in that: the smart identifying apparatus further comprises a battery circuit, wherein the processing circuit is configured such that, if the battery circuit detects that a power is lower than a predetermined value, the processing circuit can set a rule for the communicating circuit to attempt to communicate with the IOT gateway according to the power.