The utility model discloses an open-circuit prevention protective circuit for end screen grounding. The open-circuit prevention protective circuit for end screen grounding comprises a pin which is lead out from an end screen and is characterized by comprising a gas discharge tube, a piezoresistor and a transient voltage suppressor diode which are connected in parallel between the end screen-lead pin and a ground end. The open-circuit prevention protective circuit protects the connection between the end screen and the ground, ensures the safety of a transformer, and prevents accidents caused by an open circuit of an end shield grounding cable. The open-circuit prevention protective circuit does not affect normal work of equipment in normal times, does not affect a normal flow direction of end shield current and does not affect normal measurement of the end shield current. If the grounding is abnormal, the open-circuit prevention protective circuit is conducted in different grades according to voltage classes, so that a large open circuit dynamic range is prevented; and the open-circuit prevention protective circuit is small in size and reliable, and convenient to install on site. The open-circuit prevention protective circuit is suitable for preventing the open circuit of all kinds of high voltage insulation grounding.