The invention relates to the technical field of electric power, and discloses a lightning arrester used for a transformer substation. The device includes an installation base, the top of the installation base is fixedly provided with a hollow support column, and the top of the hollow support column is fixedly provided with a sealing bottom plate. When the lightning arrester used for the transformer substation is connected with a ground wire, the ground wire is clamped between a jig and an L-shaped jig, since the L-shaped jig is fixed, the ground wire can squeeze the movable jig, and a conductive needle thus can be inserted in a clamp groove on the bottom of a conductive rod; in this way, thunder and lightning can be introduced in a thunder-and-lightning introduction core through a main lightning receiving rod and a secondary lightning receiving rod, then thunder and lightning are transmitted to the conductive needle through the conductive rod, and thunder and lightning can be introduced underground through the ground wire. When the ground wire is taken down, a spring and a limiting block make the conductive needle separated from the inside of the clamp groove of the conductive rod,then the conductive function of the device can be broken, in this way, installation and dismantling of the ground wire are effectively facilitated, and the installation efficiency of the ground wireis improved.