The invention discloses a preparing method of high-performance easy-to-demold resin sand for nodular cast iron. The resin sand is prepared from 40-50 parts of forsterite powder, 3-5 parts of silica sol, 1-3 parts of boron glass powder, 0.01-0.02 part of sodium lignin sulfonate, 5-9 parts of pyrophyllite powder, 2-4 parts of phenolic resin powder, 5-8 parts of pyrite powder, 4-7 parts of gypsum powder, 2-4 parts of epoxy resin powder, 0.3-0.5 part of samarium oxide, 1-3 parts of alumina whiskers, 1-3 parts of a graphene PVA emulsion, 2-4 parts of boron nitride, 1-3 parts of ferric oxide, 1-2 parts of silicon carbide, 1-3 parts of fused alumina zirconia powder, 0.2-0.5 part of cerium oxide and 0.4-0.8 part of a vulcanizing agent. According to the resin sand, through the reasonable cooperation of the components, the content of resin and a curing agent is reduced, the performance of the resin sand is improved, the ash content and water content of the resin sand are reduced, and therefore the quality of a casting is improved, the gas volume is reduced, meanwhile the quality of reclaimed sand is improved, and good circulation is formed.