A piston pump is a type of positive displacement pump where the high-pressure seal reciprocates with the piston. While piston pumps can be used to move liquids or compress gases, they have several distinct advantages. First of all, they can operate in wide range of pressures. High pressure operation can achieved without strong effect on flow rate. Secondly, piston pumps can deal with viscous media as well as media containing solid particles

The two main types of piston pump are the lift pump and the force pump. Both types may be operated either by hand or by an engine.