The invention belongs to a hydraulic component and particularly relates to a double-modulus gear pump, wherein driving gear small-modulus teeth (5-2) are formed on a driving gear (5); multiple driving gear large-modulus teeth (5-1) are uniformly distributed among the driving gear small-modulus teeth (5-2); driven gear small-modulus teeth (10-3) are formed on a driven gear (10); the driving gear small-modulus teeth (5-2) and the driven gear small-modulus teeth (10-3) are transmission teeth; and the clearance seal is formed among the two end surfaces of the driving gear (5) and the driven gear (10), a side plate (4), a support sleeve (6), a front cove (1) and a rear cover (8). The double-modulus gear pump provided by the invention is in a double-tooth shape, can be used for greatly enhancing the discharge quantity of the gear pump and has the advantages of relatively compact structure, light weight, low pulsation and stable transmission; and the temperature change is small after the double-modulus gear pump operates for a long time.