The invention relates to a line interval secondary error prevention method and device for an intelligent substation monitoring platform, which is used for performing secondary error prevention judgment on a 220KV line longitudinal differential protection device pressure plate, a 220KV line longitudinal distance protection device pressure plate or a 110KV line protection device pressure plate; themonitoring system collects the current protection device operating state, the pressure plate throw-off state and the change station real-time measurement value data and the like in real time, so thatthe throw-off operations of the secondary device soft and hard pressure plates in an operating state of the intelligent substation related line are subjected to feasibility evaluation through the judgment of the error prevention method; and a lockout alarm can be carried out for the operations having safety hazard and not conforming to a rule, thereby ensuring the safe operation of the protectiondevice pressure plate and avoiding inconsistent throw-off behaviors of the virtual loop link pressure plate and the protection function pressure plate.