The invention relates to a compatible mechanism for pumping liquid and exhausting air. A motor 1 is electrified to rotate so as to drive a motor gear 15 and drive a planetary gear 25 to roll along an outer gear ring 2, drive a
planet carrier 24 to rotate, drive a planetary gear 25A to roll along the outer gear ring 2, drive a
planet carrier 24A to rotate, and drive an eccentric
crank shaft 19 to rotate, so that thrust for a sliding connecting piece 20 is formed through conversion to push, pull and compress a
capsule; four working processes of stretching, air inflow (liquid feed), compressing, and air outflow (liquid
discharge) are generated; and an air inlet (liquid inlet) or an air outlet (liquid outlet) of each working
station is communicated with an inlet or an outlet of a shell 5 through a diversion trench on a diversion trench transition piece 7. According to the invention, a water outlet working
station is adjusted through increasing or decreasing sealing capsules 18, or the rotating speed of the eccentric
crank shaft 19 is adjusted through adjusting the
stage number of a planetary retarding mechanism, so that the compressing speed is adjusted, and the liquid outlet volume (air outlet volume) is adjusted. The compatible mechanism for pumping the liquid and exhausting the air is commonly used in fields of
medical treatment, scientific research and the like, and various occasions such as
water sampling analysis, a high-grade coffee
machine and the like; and the working media can be air and liquid.