The present disclosure provides an anti-rotation mechanism for an electrode terminal post of a lithium-ion battery, the anti-rotation mechanism for the electrode terminal post of the lithium-ion battery is an insulative piece, the insulative piece is provided on an electrode terminal post base which is fixedly connected to the electrode terminal post, and the insulative piece is also fixedly connected to an inner wall of a battery case of the lithium-ion battery. The rotation of the electrode terminal post of the lithium-ion battery can be effectively prevented through the insulative piece which is provided on the electrode terminal post base and is fixedly connected to the inner wall of the battery case of the lithium-ion battery.