In the present work, multi-level resistive switching (RS) in W/Co:TiO2/FTO structures induced by a multi mixed mechanism was studied. It was found that the devices could be reproducibly programmed into three non-volatile resistance states. And the directly switching between any resistance states was realized. This increases the operation speed and lowers the complexity of controlling circuit of multi-level non-volatile memory. (C) 2017 Elsevier Ltd. All rights reserved.