The utility model provides a slag way flow direction switching system of blast furnace slag, which is mainly composed of a main slag trench channel, a cross travelling trolley and a switching channel; the main slag trench channel is connected with a blast furnace; above the cross travelling trolley, the switching channel is arranged below the cross travelling trolley; the blast furnace slag flows into the cross travelling trolley from the main slag trench channel; due to movement of the cross travelling trolley, the blast furnace slag flows into a water quenching channel or a direct cotton manufacturing channel or a dry slag field channel from the cross travelling trolley, and therefore, process treatment requirements are realized; and slag way flow direction switching of the blast furnace slag in the flowing process is realized. According to the slag way flow direction switching system, on the premise of not changing the existing blast furnace slag discharging manner and the existing processes, such as dry slag fields, switching among the main slag trench channel, the direct cotton manufacturing channel, the water quenching channel and the dry slag field channel is considered; the slag way switching of the blast furnace slag in the flowing process is realized; the different process treatment requirements are realized; and furthermore, when accidents happen, a slat way can be switched into the dry slag field channel in time, and therefore, the safety is ensured.