The invention discloses a semi-submerged platform and an anti-overturning system for the same. The anti-overturning system comprises a ballast pump system, an air compressing system, at least one first ballast compartment and at least one second ballast compartment, wherein the ballast pump system comprises a ballast water header pip, at least one ballast pump and a plurality of ballast water branch pipes; the air compressing system comprises a compressed air header pipe, at least one ballast air compressor and one or more compressed air branch pipes with compressed air valves; each first ballast compartment is communicated with outside air through a first vent pipe, is communicated with outside seawater through a first seawater introducing pipe with a seawater introducing valve, and is connected to the ballast water header pipe through the one or more ballast water branch pipes; and each second ballast compartment is communicated with the outside air through a second vent pipe with a vent valve, is communicated with the outside seawater through a second seawater introducing pipe with a seawater introducing valve, and is connected to the compressed air header pipe through the at least one compressed air header pipe. According to the anti-overturning system disclosed by the invention, anti-overturning torque can be supplied rapidly to keep a platform floating.