A mounting structure for slot paper in a motor stator. The slot paper is embedded in stator slots and includes a paper bottom, a paper side, and a paper front. A lug boss is protruded between two adjacent tooth block segments and protrudes from the inner wall of an outer ring. Two ends of the slot paper extend out of each stator slot. Two ends of the paper bottom are locked between the lug bosses respectively arranged on the upper end insulator and the lower end insulator. One end of each tooth block segment is provided with a clip slot and the paper front near the opening is embedded therein. The structure is simple, has a precise slot paper positioning function, does not occupy space of the stator slot, maximizes the slot filling ratio of the slots, and thus improves the overall performance of the motor.