The invention discloses a reciprocating suction and drainage pump with planar two-band rotary rotors. The reciprocating suction and drainage pump with the planar two-band rotary rotors comprises pumpcovers, a left end cover, the left rotor, the right rotor, a shaft, a pump body, a sliding board and a right end cover, wherein the two ends of the pump body are connected with the pump covers throughbolts; the pump covers are connected with the left end cover or the right end cover through bolts; the shaft penetrates through the pump body and is provided with the left rotor and the right rotor;the sliding board is arranged between the left rotor and the right rotor; the pump body is provided with a balance groove, a high-pressure drainage hole and a sliding board groove which communicate with one another, and the high-pressure drainage hole is formed in the middle of the right side of the sliding board groove; the middle of the sliding board is provided with a sliding board balance hole, the bottom face of the sliding board is provided with a curved face groove structure, and the two ends of the sliding board are provided with curved face protruding structures; and the opposite faces of the left rotor and the right rotor are warped curved faces. The volume is changed through the pair of planar two-band rotary motors, and by arranging the sliding board balance hole, the balance groove and the high-pressure drainage hole, the problem that pressure of an outlet is too high is solved.