The invention relates to barrier slurry, in particular to plasma display screen barrier slurry and a preparation method thereof. The plasma display screen barrier slurry comprises 60 to 75 percent of glass powder and 25 to 40 percent of organic carrier, wherein the glass powder comprises 25 to 35 percent of diboron trioxide (B2O3), 20 to 30 percent of barium oxide (BaO), 5 to 10 percent of phosphorus pentoxide (P2O5), 0 to 20 percent of zinc oxide (ZnO), 0 to 20 percent of aluminum oxide (AL2O3) and 0 to 15 percent of copper oxide (CuO), ceric oxide (CeO2), lithium oxide (Li2O) or sodium oxide; and the organic carrier comprises 3.0 to 15 percent of polymer, 76 to 95 percent of organic solvent, 1.5 to 16 percent of film-forming auxiliary agent and 0.1 to 0.9 percent of gas-phase method silicon dioxide (SiO2) powder. By the plasma display screen barrier slurry and the preparation method thereof, dispersing property of the glass power is improved; levelling property and thixotropic property of the barrier slurry are improved; the defects of sinking, bubbling and the like of the barrier slurry subjected to coating and sintering are overcome; the manufacturing process is simple; the finished product ratio is high; and mass production is performed easily.