The invention belongs to the technical field that when a vehicle runs with specific actions or under specific conditions or being operated by a driver, the responsivity is adopted as the feature and discloses a large-size vehicle body automatic leveling system and method based on six-point support. The large-size vehicle body automatic leveling system comprises a controller, a double-shaft tilt angle sensor, a human-computer interface, an alarm device, six support legs, six direct current motor drivers and six Hall sensors. By means of the large-size vehicle body automatic leveling system, thehighest point in a leveling support leg is maintained to be unchanged, remaining support points move upwards synchronously to be aligned with the highest point, and when all the remaining points reach the position of the highest point, a vehicle body is in the horizontal state; at the force adjustment stage, it is guaranteed that all tyres leave the ground and do not play the support role, and the whole vehicle body is supported by the six support legs; meanwhile, fine adjustment is conducted, and it is guaranteed that the six support legs are stressed uniformly. By means of the large-size vehicle body automatic leveling system, automatic leveling of a platform can be achieved in an outdoor unstructured environment; and the system has the advantages of being high in leveling precision, speed and reliability, great in stability and the like and is particularly applicable to the electronic equipment vehicle-mounted platform or various campsite motor homes.