A mop assembly and a pedal mop bucket. A water storage bucket (1) is used for containing water and cleaning a mop. After the mop is cleaned in the water storage bucket (1), the mop is put into a dewatering basket (26) in a dewatering bucket (2). An operator treads a pedal mechanism (24) to control a driving mechanism to output rotary motion so as to drive the dewatering basket (26) to rotate, and the mop is dewatered under the action of the centrifugal force generated through quick rotation. The water storage bucket (1) and the dewatering bucket (2) are separately arranged, and both are detachably fixed through a simple mechanical structure. The dewatering bucket (2) can be put into the water storage bucket (1) for packaging, and thus the product packaging volume is reduced and the space and the transportation cost are greatly saved.