The invention relates to a water turbine guide vane shear pin shear signal detection system which comprises shear pin shear signal sensors, a shear pin detection relay, a fault shear pin serial number display module and an alarm module. The shear pin shear signal sensors are installed on friction devices of a water turbine set. The number of the shear pin shear signal sensors is the same as the number of shear pins. Normally open contacts of the shear pin shear signal sensors have access to the fault shear pin serial number display module, normally closed contacts of the shear pin shear signal sensors have access to an excitation loop of the shear pin detection relay, and a normally closed auxiliary contact of the shear pin detection relay has access to the alarm module. According to the water turbine guide vane shear pin shear signal detection system, the shear pin shear signal sensors are arranged for detecting the working states of the shear pins, the fault shear pin serial number display module and corresponding connection circuits are arranged for displaying fault shear pin serial numbers, malfunction elimination is not needed, a fault guide vane can be directly positioned, and the defect treatment time is greatly shortened.