The invention discloses a pump-free lithium ion flow battery and belongs to the field of a chemical energy-storing battery. The pump-free lithium ion flow battery comprises a plurality of battery subsystems, an anode liquid preparation tank, a cathode liquid preparation tank, an anode liquid collection tank, a cathode liquid collection tank, an anode conveying tank and a cathode conveying tank. An electrode suspension solution is pushed by gravity and inert gas pressure to circularly flow, so as to avoid using a pump. The pump-free lithium ion flow battery has the advantages of simplicity in operation and convenience for controlling, reduces mechanical loss of a battery system and improves the whole efficiency and the safe use performance of the battery.