The invention provides an input tripping method and system preventing single event upset malfunction. The input system comprises a power source module, a tripping module, a input module, a signal module, a human-computer interface module and at least two micro-processor modules, the power source module is connected to the tripping module, the input module, the signal module and the human-computer interface module in a power supply mode, and when the at least two microprocessor modules both output outlet signals after a uniformly set delay time respectively, a tripping signal is output to the tripping module; or the outlet signals both output by the at least two microprocessor module after a uniformly set delay time respectively are output to and gate logics with the number of an odd not smaller than three simultaneously, after and gate logic processing, the processed result is voted and judged, the tripping signal is output to the tripping module, and the switch is tripped. According to the input tripping method and system preventing the single event upset motion, outlet mistrip caused by single event upset malfunction when information of a memory in which information is stored in a CPU module changes, and the reliability of outlet trip is improved.