The invention discloses high-performance wet green sand for a 
steel casting and a preparing method of the high-performance wet green sand. High-performance wet green sand is composed, by weight, of 40-60 parts of 
zircon sand, 15-20 parts of sea mud, 10-15 parts of ardealite, 25-35 parts of 
diopside, 20-30 parts of polyphenyl granule, 5-10 parts of 
sodium fluoroaluminate, 15-20 parts of coconut shell 
powder, 10-15 parts of crushed 
brick powder, 4-8 parts of hydroxypropl 
xanthan gum, 3-6 parts of sulfonated 
asphalt powder, 5-10 parts of bitter ling soil, 2-4 parts of 
calcium sulfite, 3-5 parts of poly aluminum 
chloride, 4-6 parts of polyoxyethylene, 2.5-4.5 parts of 
sodium hexametaphosphate, 5-10 parts of modified kaolin and a proper amount of water. The wet green sand is good in comprehensive performance, has the high green compression strength, the high compaction rate and the low thermal expansivity, also has the good high-
temperature resistance, ventilating performance and fluidity and can effectively overcome the defects that air holes, scabbing, sand clamping, sand holes and the like can happen on the 
steel casting, the surface quality of the 
steel casting is improved, the finished product rate of the steel 
casting is increased, and the high-performance wet green sand has important 
economic benefits.