A phosphor constant temperature and pressure spraying device of a plasma display panel with shadow mask belongs to plate television manufacturing equipment, which includes a spray gun (1) and a slurry tank (9). The slurry tank (9) is connected with a feed port (10), an exhaust port (11) and a material discharging port (12). The feed port of the spray gun (1) is respectively connected with a compressed air source (8) and the slurry tank (9) and is characterized in that the tank wall of the slurry system tank (9) is a double-layer structure. Liquid medium is arranged in the tank wall and is connected with a heat exchange system (2). The compressed air source (8) is communicated with the space on the upper part of the liquid in the slurry tank (9) through an air pipe. The air pipe is equipped with a constant pressure valve (6). A stirring shaft (3) is installed in the slurry tank (9) and is driven by a stirring motor. The present invention solves a problem that a present spraying system sprays unevenly and has the advantages of simple structure and good spraying effect.