A communication method and an IoT device in a multi-MAC (Media Access Control)-operating environment. The communication method in the multi-MAC-operating environment, including synchronous MAC and asynchronous MAC, includes periodically transmitting, by the IoT device included in the multi-MAC-operating environment, a first message to a first device; determining, by the IoT device, whether to transmit a second message; transmitting, by the IoT device, a preamble packet to a second device, to which the second message is to be transmitted, when the second message is determined to be transmitted; and transmitting, by the IoT device, the second message to the second device.