Variable-volume garbage can of sweeping car

The invention provides a variable-volume garbage can of a sweeping car. The garbage can is divided into three areas including a clear water tank area, a normal-pressure sewage tank area and a negative-pressure sewage tank area, wherein sewage in the negative-pressure sewage tank area is pumped into the normal-pressure sewage tank area by a sewage pump, the interconversion of the clear water volume and the sewage volume between the clear water tank area and the normal-pressure sewage tank area can be realized by virtue of soft variable-volume walls, garbage and sewage in the normal-pressure sewage tank area and the negative-pressure sewage tank area can be simultaneously poured by discharge doors, and simultaneously, the normal-pressure sewage tank area and the negative-pressure sewage tank area are sealed. The volume interconversion between the clear water tank area and the sewage tank area can be realized by virtue of the soft variable-volume walls, so that the utilization rate of the volume of the garbage can is increased, and the uninterrupted working time of the sweeping car is greatly extended.