The invention relates to an inner wall cleaning tool for a spent fuel storage sleeve. The inner wall cleaning tool comprises a long rod, an impurity sucking assembly and a cleaning assembly, wherein the long rod stretches into a spent fuel pool from a maintenance bridge above the spent fuel pool; the impurity sucking assembly is fixed to the lower end of the long rod; and the cleaning assembly is fixed to the lower end of the impurity sucking assembly. The impurity sucking assembly comprises a submerged pump and a collecting pipe. Impellers in the submerged pump can rotate in the positive direction and in the negative direction and rotate in a multi-gear variable-speed mode, and therefore a bidirectional water pressure difference is formed between the inner side and the outer side of an opening of the collecting pipe. When the impellers rotate in the positive direction, the physical state that the pressure in the collecting pipe is lower than the pressure outside the collecting pipe is formed, and target foreign matter is sucked into the collecting pipe. A filter screen structure is arranged in the collecting pipe. The cleaning assembly comprises brush seats and brushes arranged on the brush seats. The upper ends of the brush seats are connected with the lower end of the collecting pipe. The upper end of the collecting pipe is connected with the lower end of the submerged pump. The upper end of the submerged pump is connected with the lower end of the long rod. By the adoption of the inner wall cleaning tool, the inner wall of the storage sleeve is cleaned conveniently, and safe conditions are created for water outlet, temporary storage, and treatment or disposal of a spent fuel storage grillage.