The present invention relates to the technical field of breast pumping products, in particular to a breast pump, which includes a breast milk collector, a suction source and a breast shield. The outlet is connected to the breast milk collector through the first hose, the breast milk collector is connected to the suction port of the suction source through the second hose, and the air release channel is connected to the air discharge port of the suction source through the third hose, and the breast shield is covered on the breast during use , since the breast shield is separated from the breast milk collector, there is no need to support it by hand, start the suction source, and the suction source will inhale, and the air pressure in the breast milk collector and breast shield will become negative pressure. When the air pressure is lower than the internal pressure of the breast, the milk will flow from The nipple is sucked into the breast shield, and then the suction source is deflated. After deflation, the pressure in the breast shield increases instantaneously, while the pressure of the breast milk collector is still in a negative pressure state. Under the action of the pressure difference, milk flows from the breast shield through the first hose Rapid flow to the breast milk collector for no milk residue.