An Internet of Things (IoT) system is illustrated, which has a power switch and an IoT device. The power switch electrically connected to the IoT device provides power to the IoT device. The IoT device has a memory unit, a control unit and a networking unit. When the power switch switches the control unit to a power supplying state from a non-power supplying state, the power switch generates a switch surge signal, and transmits the switch surge signal to the control unit, and the control unit receives the switch surge signal and executes a reset control command stored in the control unit, so as to reset the IoT device. The IoT system of the present disclosure utilizes the switch surge signal to reset the IoT device be reset without installing a reset button.