The invention discloses a media access control method of an underwater magnetic induction wireless sensor network, wherein the underwater magnetic induction wireless sensor network comprises a plurality of magnetic induction wireless sensor nodes, each magnetic induction wireless sensor node comprises a transceiver antenna, a working module and a wake-up module, and the method comprises the following steps: the wake-up module of the first node in the plurality of magnetic induction wireless sensor nodes receives a wake-up signal sent by the second node via the transceiver antenna of the firstnode; the wake-up module of the first node generates a wake-up instruction according to the wake-up signal and sends the wake-up instruction to the working module of the first node; the working moduleof the first node converts from a sleep state into an active state when receiving the wake-up instruction, so that the first node performs data transmission with the second node through the transceiver antenna; and after the data transmission is completed, the working module of the first node converts from the active state into the sleep state. According to the method of the invention, the reliability of information transmission can be improved, and the power consumption can be reduced.