The invention discloses a monitoring device for gas insulated switchgear (GIS) thunder-and-lightening invasion overvoltage. The monitoring device comprises a voltage collecting module, a data transmission module and a data collecting storing module which are connected in sequence, the voltage collecting module comprises a contact terminal, a low-voltage voltage-dividing capacitor, a low damping voltage divider, an amplifier, a signal sending unit and a power module, the contact terminal is arranged at the position of an insulator of the outer wall of a GIS sleeve, one end of the low-voltage voltage-dividing capacitor is connected with the contact terminal, the low damping voltage divider is in parallel connection with the low-voltage voltage-dividing capacitor, a voltage-dividing output end of the low-voltage voltage-dividing capacitor is connected with an input end of the amplifier, an output end of the amplifier is connected with the signal sending unit, the signal sending unit is connected with the data collecting storing module through the data transmission module, and a power output end of the power module is respectively connected with the amplifier and the signal sending unit. The monitoring device for GIS thunder-and-lightening invasion overvoltage has the advantages that the GIS thunder-and-lightening invasion overvoltage in high-frequency band can be effectively detected, the collecting accuracy and capacity of resisting disturbance are high, and the stability is good.