The utility model relates to a large-displacement sliding slab self suction pump, comprising a pump body 1, a curve in the pump body comprises an arc and a constant acceleration curve; a suction mouth and a discharge mouth are arranged in the radial direction; the two half liquid storage chambers are arranged at the bottom of the pump body; the suction mouth is communicated with an inlet of the pump through one liquid storage chamber; the discharge mouth is communicated with an outlet of the pump through the other liquid storage chamber; the two half liquid storage chambers are communicated by a small hole; a groove is radially arranged on the inner rotor 7; a sliding vane 6 is arranged in the groove; the inner rotor 7 with the sliding vane 6 is hotly sleeved on a pump shaft 21; the inner rotor 7 and the pump shaft 21 are arranged in the pump body 1 together, and are supported by the two pump bearing end covers 5; two mechanical sealings 8 are arranged at the shaft ends; a coupling 11 is arranged at the extension end of the pump shaft 21; and a safety valve 30 is arranged in the upper part. Thus the large-displacement sliding slab self suction pump is formed. The large-displacement sliding slab self suction pump improves liquid flowing state, and reduces vibration and noise during pump operation.