Characteristics of fire flooding are the joint result of complex physicochemical processes of fire flooding and geological conditions of reservoirs，which serve as an important basis for plan design and tracking control of fire flooding. With the help of a one-dimensional combustion tube apparatus for heat tracking compensation，we comparatively analyzed the displacement characteristics of linear fire flooding of heavy oil reservoirs with different properties and compared them with those of flue gas flooding. The results show that the viscosity of crude oil significantly affects the liquid production rate by fire flooding. For the low viscosity crude oil，most of the crude oil with the high initial liquid production rate at the stage is exploited in the early and middle stages of fire flooding. While for the high viscosity crude oil，most of the crude oil with the low，or even no initial liquid production rate is exploited in the middle and late stages of fire flooding. The water cut during fire flooding mainly depends on the initial water saturation of the formation（water saturation before fire flooding）. When the initial water saturation of the formation is higher than the irreducible water saturation，the water cut is high at the beginning of fire flooding，then gradually decreases and levels off. The production performance at the initial stage of fire flooding（gas injection volume is less than one time of pore volume）is similar to that of flue gas flooding. In the continuous development，the fire flooding still maintains a stable oil recovery rate，while the recovery increment by the flue gas flooding gradually declines. The recovery by fire flooding has an approximately linear relationship with cumulative gas injection volume，which indicates that gas injection volume is crucial to the effect of fire flooding.