In this work, the desired reduced graphene oxide was obtained by thermal reduction and hydrothermal reduction, and it was fluorinated to obtain the fluorinated graphene (FG-0.95) required for the experiment, and then the electrochemical performance of fluorinated carbon as cathode active material of potassium primary battery was studied. Comparing the discharge curves of the fluorinated graphene and commercial fluorinated graphite (Daikin), it can be concluded that the discharge voltage platform of the FG-0.95 sample is more stable than the discharge platform of the Daikin sample, and its specific capacity is much larger than that of the Daikin sample, so that the electrochemical performance of FG-0.95 is better. The FG-0.95 sample is more suitable as a positive electrode material for a potassium fluorinated carbon primary battery.