The display-signal detection device comprises a first connector for receiving the voltage, clock and data transmission signals between a main board and a display. The first connector is coupled with abuffering mould and a voltage comparator, in which, the buffering mould is used for receiving clock and data transmission signals and buffering the signals, the voltage comparator is used for receiving voltage transmission signals and comparing the signals to obtain the result. The buffering mould and the voltage comparator is respectively coupled with a programmable logic device for monitoring whether there is abnormal output signals, if 'yes', corresponding lead digit is taken, if 'not', a pre-set code is displayed. The logic device is couple with a displaying mould to receive and display the lead digit or pre-set code where the abnormal output signal occurs. Advantage: solved overlabor work of hand signal-detecting in display-signal detecting device.