An ear tag module includes a rod member, a spike, a circuit component, and a temperature sensor. The spike is disposed on one side of the rod member, and the circuit component is disposed on another side of the rod member. The temperature sensor is electrically connected to the circuit component. When the spike penetrates an ear, the ear is in contact with a sensing area of the rod member, and the temperature sensor is located in the rod member to detect a temperature of the ear and transmit at least one temperature sensing information to the circuit component.