The invention discloses a lithium ion battery tab which comprises a switching positive tab and a switching negative tab which are arranged on a lithium ion battery. Tab glue is arranged on the switching positive tab and the switching negative tab, and a positioning device is arranged on the tab glue and used for positioning aluminum-plastic films in folding. The tab glue of the switching tabs is provided with two positioning projections or lugs which are positioned on two side surfaces of the switching tabs, the shell-entering position of a bare cell can be accurately positioned by the aid ofthe positioning projections or lugs on one surface of each switching tab, and alignment of the aluminum-plastic films after turnover can be accurately controlled by the aid of the positioning projections or lugs on the other surface of each switching tab. On one hand, poor exposure of packaged tab glue due to the inaccurate shell-entering position of the bare cell in packaging can be prevented, exposure consistency of the tab is improved, and assembly positioning accuracy of a battery pack assembled by the cell is improved. On the other hand, top edge sealing dislocation can be decreased and even eliminated, and cell length consistency is improved. The lithium ion battery tab is applied to the technical field of batteries.