The invention discloses a stand-by safety chain monitoring and protecting device for a wind power generation control system, comprising a power supply, a cable-twisting switch, an engine-room vibration protection switch, a grid protection switch, a converter protection switch, an engine room and tower support emergent stop button, a distributed heartbeat signal monitoring switch, a rotary speed protection switch and a safety chain relay, wherein the power supply generates power signals and is respectively connected in series with the cable-twisting switch, the engine-room vibration protection switch, the grid protection switch, the converter protection switch, the engine room and the tower support emergent stop button, the distributed heartbeat signal monitoring switch, the rotary speed protection switch and the safety chain relay. The monitoring and protecting device adopts an active safety design, runs independent of a PLC system and monitors relevant signals at real time; and when incidents endangering the safety of a machine set occur, the monitoring and protecting device actively controls a pitch system to realize full feathering, thereby achieving the safe shut-down of the machine set.