The invention provides an insulating block mounting device, which comprises a table board and a driving device. A positioning device for fixing a to-be-mounted isolating switch is arranged on the table board and provided with a plurality of ejection blocks matched with insulating blocks. The driving device drives the ejection blocks to move close to or away from the to-be-mounted isolating switch.The insulating block mounting device has advantages that by the device simple in structure, safe and reliable, an insulating block mounting process is free of manual mounting operation, and accordingly safety in operation is further improved.