The invention discloses a Mars floating detection system. The system comprises a floating system, an inflation system and a landing cabin, wherein the floating system comprises an overpressure balloon, a tying rope, an instrument cabin and a track controller, the track controller comprises a main rod, a main wing, an empennage and a balance weight, the main wing is connected to the middle of the main rod, the empennage and the balance weight are arranged at the two ends of the main rod respectively, the instrument cabin is tied below the overpressure balloon through the tying rope, and the track controller is tied below the instrument cabin; the inflation system is arranged in the landing cabin and used for inflating the overpressure balloon. The system is carried by a lander to reach thesurface of the Mars, and when the meteorological condition of the surface of the Mars is good, the inflation system inflates the overpressure balloon until the floating system lifts off and is separated from the landing cabin; then the floating system is separated from the inflation system, and the inflation system is left in the landing cabin; and after the floating system reaches a preset height, detection work is started, and different areas are detected through Mars atmospheric motion. Movement is not limited by Mars topography and geomorphism, and the detection range is wider.