The utility model discloses a Pascal non-circular gear-driven four-blade differential pump. The existing differential pump has the problems of difficulty in optimizing pressure pulsation, liquid trapping and the like. A first Pascal non-circular gear and a second Pascal non-circular gear are respectively fixed to an input shaft; a first conjugate Pascal non-circular gear and a first impeller are respectively fixed to an output shaft, and the first conjugate Pascal non-circular gear meshes with the first Pascal non-circular gear; a second conjugate Pascal non-circular gear and a second impeller are fixed to a shaft sleeve, and the shaft sleeve is flexibly sheathed on the output shaft; the second conjugate Pascal non-circular gear meshes with the second Pascal non-circular gear; a pump casing is sequentially provided with a first liquid discharge port, a first liquid suction port, a second liquid discharge port and a second liquid suction port in the circumferential direction; the first impeller and second impeller are respectively provided with two blades; and the inside of each blade is provided with a one-way relief valve. The differential pump has the advantages of large discharge capacity, stable flow rate and adjustable non-uniform velocity rules, and effectively solves the problem of liquid trapping.