The invention relates to a voltage divider assembling auxiliary device which comprises a base and a supporting module used for supporting an insulation barrel. A limiting groove for limiting horizontal rolling of the insulation barrel is formed in the supporting module. The supporting module is fixed to the base. When a voltage divider is assembled, the insulation barrel is fixed to the voltage divider assembling auxiliary device through a travelling crane, and then a resistor, a capacitor, a foundation, a grading ring and other parts are assembled; the height of the insulation barrel does not need to be adjusted by the travelling crane or a storage battery fork truck in the whole process, and the voltage divider assembling auxiliary device is high in assembling efficiency, safe and reliable and solves the problems that an existing voltage divider is low in assembling efficiency and safety is difficult to guarantee.