A piston type pressurization pump comprises a pressurization cylinder and a sliding device that is slidably arranged in the pressurization cylinder. The sliding device comprises a piston that is reciprocally slidable between a first side and a second side of the pressurization cylinder, and a first check valve arranged in a channel of the piston. The piston forms first and second chambers with respect to the first and second sides of the pressurization cylinder. An inlet and an outlet of the pressurization cylinder are respectively set in communication with the first and second chambers. The channel of the piston is in communication with the first and second chambers. The first check valve prevents liquid contained in the second chamber from flowing through the channel of the piston into the first chamber. As such, when the piston is discharging liquid, the first check valve prevents the liquid of the second chamber from flowing backward to the first chamber so as to allow the pump to steadily supply pressurized liquid.