The invention provides a distributed access method of an elastic long-distance wireless transmission system based on TDMA. The system operates according to the following steps, first step, a node accesses the network, monitors and synchronizes a starting time of the frame; second step, the node sends network access request information at a starting time slot of the next frame, waits for a neighbornode to broadcast time slot occupation information, and constructs a time slot occupation situation of the neighbor node within two hops; third step, the node performs time slot occupation accordingto its own ID and a time slot selection algorithm, and broadcasts the occupation result; and fourth step, after the two-hop neighbor finishes updating the new node information, the node accesses the network and transmits data according to the time slot transmission algorithm. The frame structure, the node network access process and the time slot transmission algorithm provided by the invention obtain higher throughput in an elastic long-distance transmission network and have higher transmission stability.