The utility model discloses a safety device about platform can make things convenient for crewman's upper and lower ocean exploitation platform safely, provides means for the upper and lower safety of platform. This safety device about platform is equipped with the running -board including the ladder frame in the terraced frame, the one end of ladder frame is connected with locking mechanism's pivot and the pivot both ends installation fixation nut outside the ladder frame. This instrument simple structure, workable, the cost of manufacture is low, carries and convenient to use, can show the safety of platform about improving, has fine result of use.