The utility model relates to an improved dewatering structure of a mop, which is characterized in that: a dewatering tank with a plurality of holes is arranged in a bucket body with a handle and is linked with a transmission mechanism at the bottom of a bucket through a one-way bearing rod, and the transmission mechanism controls the dewatering tank to rotate; wherein the transmission mechanism is provided with a base on which two supporting pieces stand, and a pedal as well as a first gear set, a second gear set and a third gear set are pivoted on a supporting seat through shaft rods and are mutually linked; one end of the pedal is of a pedaling surface, and the other end thereof is of a ratchet end; and the pedal is driven by the ratchet end of the pedal and the first gear set to link the second gear set and the third gear set, and the third gear set is rotatably pivoted with the dewatering tank of a one-way bearing group. The transmission between gears is stable, and the consumption of kinetic energy is reduced; a user does not need too much effort when pedaling so as to realize the dewatering function of the mop; and the configuration of the reasonable space of components is provided to prevent the components from being mutually interfered with each other so as to reduce the damage to the components.