The invention discloses a coking furnace roof dust removing device. A supporting seat is arranged on a base line of a furnace roof, and a fan and a dust remover are fixed onto the supporting seat. The coking furnace roof dust removing device further comprises a main air pipe and a plurality of air collecting hoods, wherein the air collecting hoods right cover the outer sides of two adjacent coke side small furnace heads, one end of the main air pipe is communicated with an air sucking opening of the fan and an air inlet of the dust remover, and the other end of the main air pipe is communicated with the air collecting hoods through branch air pipes. Each air collecting hood is formed by a collecting section and a refracting section which are connected with each other, a spiral groove is formed in the inner wall of the collecting section in the axial direction, the refracting section is in a conical shape, and a conical top portion of the refracting section is communicated with the tail ends of the branch pipes. In work, the air collecting hoods can collect flue gas dissipated out of the small furnace heads above the base line of the furnace roof together in a concentrated mode, collected flue gas enters the main air pipe through the branch air pipes and then enters the dust remover under traction of air force of the fan, the flue gas is processed, flue gas dissipation on the furnace roof is avoided, and environmental pollution is avoided.