The invention relates to a multi-communication-mode maritime search and rescue tracking buoy based on a micro control unit, being characterized in that by means of the principle that the floating state of the buoy is adjustable and drifts with the ocean current, after the ship type switch is manually started and thrown into the sea, the buoy can send its own position information in real time, andvisualizes the trajectory at the data receiving end to realize the tracking function. The buoy communicates with GSM in the offshore area and with Beidou in the offshore area. The communication mode can be automatically switched according to the signal strength according to GSM. The invention can simulate the drifting trajectory of the person falling into the water when the person falling into thewater cannot be salvaged in time, correct the predicted trajectory of the wind pressure drifting model, further provide a searching path, and realize the rapid positioning and salvage of the person falling into the water. The invention adopts modular design, has various communication modes and lower cost, and has good industrial application prospect.