The invention discloses a sedimentation furnace device and method for testing the co-combustion characteristic of solid fuel containing carbon. The sedimentation furnace device comprises a sedimentation furnace body, a pulverized coal feeding pipeline assembly and a smoke discharging assembly. The air/pulverized coal inlet end of the sedimentation furnace body is connected with the pulverized coal feeding pipeline assembly, and the smoke outlet end of the sedimentation furnace body is connected with the smoke discharging assembly. The pulverized coal feeding pipeline assembly comprises two primary air/pulverized coal pipes, a secondary air pipe and an inlet water cooling section, wherein the length difference between the two primary air/pulverized coal pipes can be adjusted. The smoke discharging assembly comprises an outlet water cooling section, an ash collection device and a smoke outlet. By the adoption of the sedimentation furnace device, study of the co-combustion characteristic of the different solid fuel containing the carbon in an intra-furnace mixing mode and an extra-furnace mixing mode can be conducted, and meanwhile study of the co-combustion characteristic of the different solid fuel containing the carbon under different blending combustion proportions and different mixing times can also be achieved. According to the sedimentation furnace device and method for testing the co-combustion characteristic of the solid fuel containing the carbon, the structure is simple, and implementation is convenient and effective; compared with an existing sedimentation furnace, co-combustion of the solid fuel containing the carbon under the actual industrial condition can be simulated more comprehensively.