The invention discloses a pressurized pneumatic feeding system and a pressurized pneumatic feeding method for coal slurry. The system comprises a control module, a coal slurry storage tank mechanism and a pneumatic pressurizing mechanism, wherein the coal slurry storage tank mechanism comprises a low-pressure coal slurry storage tank, a low-pressure coal slurry pump and high-pressure coal slurry storage tanks; the pneumatic pressurizing mechanism comprises a gas compressor, a gas source storage tank and a pressure relief tank; the control module comprises a controller; an input end of the controller is connected with a liquid sensor group, a pressure sensor group, a flow sensor group and a gas supply flow sensor. The method comprises the following steps: firstly, compression and storage ofa gas source; secondly, storage and low-pressure transmission of the coal slurry; thirdly, pneumatic pressurizing and conveying of the coal slurry; fourthly, feeding of gas raw materials. According to the pressurized pneumatic feeding system and the pressurized pneumatic feeding method disclosed by the invention, a reasonable design is adopted; pressurized transmission is carried out by utilizingpressurized gas, so that a pulse generated by a mechanical conveying mode of a high-pressure coal slurry pump is eliminated and the metering accuracy of the coal slurry is improved. In addition, investment expenses of equipment are reduced and high practicality is realized.