The invention discloses a stored energy enhancing type gypsum plaster board. A gypsum substrate is prepared from the following components in percentage by weight: 40 to 95 percent of building gypsum powder, 5 to 60 percent of a porous sizing phase-change material, 0.05 to 5 percent of a water reducing agent, 0.05 to 5 percent of modified starch, 0.5 to 10 percent of fiber and 50 to 80 percent of water, wherein the porous sizing phase-change material is prepared from a porous sizing body and a fatty acid phase-change body. The invention also discloses a preparation method of the stored energy enhancing type gypsum plaster board. The preparation method comprises the following steps: mixing the solid materials according to weight proportions, and uniformly stirring together; adding 50 to 80 percent of water and quickly stirring, thus preparing gypsum slurry; putting lower surface protection paper under a grinding tool, pouring the gypsum slurry into the grinding tool, striking off, putting upper surface protection paper, flattening and forming. The stored energy enhancing type gypsum plaster board disclosed by the invention has the advantages of low heat conductivity coefficient, moderate phase-change temperature, energy saving, consumption reducing and the like.