The invention provides a method for clearing pipelines in the manufacturing process of aluminium oxide, which is applicable to the clearance of scars generated in the pipeline transportation section in the manufacturing process of aluminium oxide, in particular to the method for clearing the scars inside the pipelines. The clearing process is characterized in that the pipeline is full of floating NaOH alkali liquor with the temperature of 93-103 DEG C in the clearing process; the NaOH alkali liquor dissolves the scars in the pipelines and the scars can be cleared by the floating and eroding of the alkali liquor. The wet clearing method of pipelines in the process of manufacturing the aluminium oxide by the sintering method can realize scar decomposition and return to the flow by utilizing the principle that alkali solution with certain temperature, concentration and flow rate can dissolve the scars, thus realizing the recycling of the pipelines for transmitting materials in the manufacturing process of the aluminium oxide and improving production capability and device productivity.