The invention discloses a data-unit-based data transmission method. The data-unit-based data transmission method comprises the steps: defining a data unit; defining identical data flow structure bodies at a sending end and a receiving end; burstifying data flow; sending and receiving the data flow; analyzing the data flow. The data unit-based data transmission method has the beneficial effects that 1) an outer-space communication protocol achieves an agreement at the sending end and the receiving end, a data protocol is a fixed rule without the need of transmission and any expand; 2) the data structure bodies are defined simply, internal codes of each data unit and data of the data unit are paired to form independent data bodies, and when the structure bodies contain a plurality of data bodies, the ranking is not limited by a sequence; 3) the data bodies of the data structure bodies can be flexibly stretched and expanded as required.