A self-wringing foam cotton mop with a labor-saving wringing operation, comprising a mop rod and a foam cotton head, wherein: the foam cotton head is rotatably connected to a bottom end of the mop rod; a wringing frame is disposed on the mop rod; during mopping, the foam cotton head is separated from the wringing frame; a squeezing mechanism capable of squeezing the foam cotton head entering the wringing frame is disposed on the wringing frame; a position of the squeezing mechanism is changeable, so that the position of the squeezing mechanism when the foam cotton head is moved upward relative to the wringing frame is different from the position of the squeezing mechanism when the foam cotton head is moved downward relative to the wringing frame; therefore, a first amount of deformation (Δh1) generated by the foam cotton head during an upward movement of the foam cotton head relative to the wringing frame is greater than the second amount of deformation (Δh2) generated by the foam cotton head during a downward movement of the foam cotton head relative to the wringing frame; wherein the squeezing mechanism is adapted for squeezing a bottom surface of the foam cotton head to realize the wringing operation; when the foam cotton head is moved up relative to the wringing frame, the squeezing mechanism enables the foam cotton head to generate the first amount of deformation (Δh1) in a thickness direction; and, when the foam cotton head is moved down relative to the wringing frame, the squeezing mechanism enables the foam cotton head to generate the second amount of deformation in the thickness direction; characterized in that: the wringing frame comprises a through hole for allowing an end surface of the foam cotton head to pass therethrough, and the squeezing mechanism is disposed within the through hole and is able to swing relative to the wringing frame; during a wringing process, the foam cotton head is rotated to allow the end surface to be aligned with the through hole; in the process that the foam cotton head enters the through hole and moves up, the squeezing mechanism that does not swing enables the foam cotton head to generate the first amount of deformation (Δh1); and in the process that the foam cotton head enters the through hole and moves down, the swung squeezing mechanism enables the foam cotton head to generate the second amount of deformation (Δh2). the foam cotton head is rotatably connected to a bottom end of the mop rod; a wringing frame is disposed on the mop rod; during mopping, the foam cotton head is separated from the wringing frame; a squeezing mechanism capable of squeezing the foam cotton head entering the wringing frame is disposed on the wringing frame; a position of the squeezing mechanism is changeable, so that the position of the squeezing mechanism when the foam cotton head is moved upward relative to the wringing frame is different from the position of the squeezing mechanism when the foam cotton head is moved downward relative to the wringing frame; therefore, a first amount of deformation (Δh1) generated by the foam cotton head during an upward movement of the foam cotton head relative to the wringing frame is greater than the second amount of deformation (Δh2) generated by the foam cotton head during a downward movement of the foam cotton head relative to the wringing frame; wherein the squeezing mechanism is adapted for squeezing a bottom surface of the foam cotton head to realize the wringing operation; when the foam cotton head is moved up relative to the wringing frame, the squeezing mechanism enables the foam cotton head to generate the first amount of deformation (Δh1) in a thickness direction; and, when the foam cotton head is moved down relative to the wringing frame, the squeezing mechanism enables the foam cotton head to generate the second amount of deformation in the thickness direction; characterized in that: the wringing frame comprises a through hole for allowing an end surface of the foam cotton head to pass therethrough, and the squeezing mechanism is disposed within the through hole and is able to swing relative to the wringing frame; during a wringing process, the foam cotton head is rotated to allow the end surface to be aligned with the through hole; in the process that the foam cotton head enters the through hole and moves up, the squeezing mechanism that does not swing enables the foam cotton head to generate the first amount of deformation (Δh1); and in the process that the foam cotton head enters the through hole and moves down, the swung squeezing mechanism enables the foam cotton head to generate the second amount of deformation (Δh2). the wringing frame comprises a through hole for allowing an end surface of the foam cotton head to pass therethrough, and the squeezing mechanism is disposed within the through hole and is able to swing relative to the wringing frame; during a wringing process, the foam cotton head is rotated to allow the end surface to be aligned with the through hole; in the process that the foam cotton head enters the through hole and moves up, the squeezing mechanism that does not swing enables the foam cotton head to generate the first amount of deformation (Δh1); and in the process that the foam cotton head enters the through hole and moves down, the swung squeezing mechanism enables the foam cotton head to generate the second amount of deformation (Δh2).