Provided are a reliability-based, real-time sensor network medium access control (MAC) communication system and method using a superframe. The superframe includes an active duration which is a time duration in which a communication is established, and a sleep duration which is a time duration in which no communication is established. The active duration includes a beacon block in which a plurality of beacon transmission nodes are respectively allocated beacon slots for transmitting a beacon frame, and a forwarding block in which each of sinks nodes is allocated a slot for unifying data regarding the sink node and data regarding sensor nodes managed by the sink node and transmit the result of unifying in order to establish a communication between the sink nodes and between each of the sink nodes and a base station.